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CHAPTER VI.
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 INJECTION.
 
1. Injection is the filling of the arteries1, veins2, or other vessels4 of animals with some coloured substance, in order that their natural arrangement may be made visible. This is, of course, a delicate operation, and needs special apparatus6, which I will now attempt to describe.
2. Syringe.—This is usually made to contain about two ounces. On each side of the part next to the handle is a ring, so that the finger may be thrust through it, and the thumb may work the piston7 as in an ordinary syringe. The plug of the piston must be “packed” with wash-leather, and fit so closely as to be perfectly8 air-tight; and if, when it has been used awhile, it is found that some of the liquid escapes past the plug into the back part of the body, it must be repacked, which operation will be best understood by examining the part. These syringes are made of various sizes, but in ordinary operations the above will be all that is needed. The nozzle is about an inch long, and polished so accurately9 that there is no escape when the pipes are tightly placed upon it dry.
3. The pipes are usually about an inch long, to the end of which are affixed10 thicker tubes so as to fit the nozzle, as before mentioned, whilst a short arm projects from each side of these, so that the silk or thread which is used to tie this artery12, &c., upon the thin pipe may be carried round these arms, and all danger of slipping off prevented. The pipes are made of different sizes, from that which will admit only a very fine needle (and this will need now and then to be cleaned, or to be freed from any chance obstruction),123 to that which will take a large pin. These sizes must always be at hand, as the vessels of some subjects are exceedingly minute.
4. Stopcock.—This is a short pipe like a small straight tap, which fits accurately upon the end of the syringe like the pipes, and also takes the pipes in the same manner. The use of this is absolutely necessary when the object is so large that one syringe full of liquid will not fill it. If no preventive were used, some part of the liquid would return whilst the syringe was being replenished13, but the stopcock is then turned as in an ordinary tap, and all danger of this effectually removed.
5. Curved needles.—These are easily made by heating common needles at the end where the eye is situated14, and bending them with a small pair of “pliers” into a segment of a circle half an inch in diameter. They are, perhaps, more convenient when the bent15 part is thrown slightly back where it commences. The pointed16 end is then thrust into a common penholder, and the needle needs no re-tempering, as the work for which it is wanted is simply to convey the thread or silk under any artery or vessel5 where it would be impossible to reach with the unassisted fingers.
6. A kind of forceps, commonly know by the name of “bullnose forceps,” will be constantly required during the process of injecting. These are short, usually very strong, but not heavy, and close very tightly by their own spring, which may be easily overcome and so released by the pressure of the fingers. When any vessel has not been tied by the operator, and he finds the injected fluid escaping, one of these “bulldogs” may be taken up and closed upon the opening. This will cause very little interruption, and the stoppage will be almost as effectual as if it were tied.
7. When the ordinary mode of injection is employed, it is necessary that the preparations be kept warm during the time they are used, otherwise the gelatine or size which they contain becomes stiff, and will not allow of being124 worked by the syringe. For this purpose we must procure17 small earthenware18 or tin pots of the size required, which will differ according to the kind of work to be done; and to each of these a loose lid should be adapted to protect it from dust, &c. These pots must be allowed to stand in a tin bath of water, under which a lamp or gas flame may be placed to keep the temperature sufficiently19 high to insure the perfect fluidity of the mixture. The tin bath is, perhaps, most convenient when made like a small shallow cistern20; but some close it on the top to place the pots upon it, and alter the shape to their own convenience.
8. We will now inquire into some of the materials which are needed in this operation; the first of which is size. This substance is often used in the form of glue, but it must be of the very best and most transparent21 kind. To make the liquid which is to receive the colours for the usual mode of injecting, take of this glue seven ounces, and pour upon it one quart of clean water; allow this to stand a few hours, and then boil gently until it is thoroughly22 dissolved, stirring with a wooden or glass rod during the process. Take all impurities23 from the surface, and strain through flannel24 or other fine medium. The weather affects this a little as to its stiffness when cold, but this must be counteracted25 by adding a little more glue if found too liquid.
9. Instead of glue, gelatine is generally used, especially when the work to be accomplished26 is of the finer kind. The proportions are very different in this case, one ounce of gelatine to about fourteen ounces of water being sufficient. This, like glue, must be soaked a few hours in a small part of the cold water, the remainder being boiled and added, when it must be stirred until dissolved. A good size may be made by boiling clean strips of parchment for awhile, and then straining the liquid whilst hot through flannel; but when the injections are to be transparent, it is of the greatest importance that125 the size be as colourless as possible. For this purpose good gelatine must be employed, as Nelson’s or Cox’s: some persons of experience prefer the latter.
10. Colours.—The size-solution above mentioned will need some colouring matter to render it visible when injected into the vessels of any animal, and different colours are used when two or more kinds of vessels are so treated, in order that each “set” may be easily distinguished27 by sight. The proportion in which these colours are added to the size-solution may be given as follows:—
11. For—
Red 8 parts of size-solution (by weight) to 1 part of vermilion.
Yellow 6 ” ” 1 chrome yellow.
White 5 ” ” 1 flake-white.
Blue 3 ” ” 1 blue-smalt, fine.
Black 12 ” ” 1 lamp-black.
Whichever of these colours is made use of must be levigated in a mortar28 with the addition of a very small quantity of water until every lump of colour or foreign matter is reduced to the finest state possible, otherwise in the process of injecting it will most likely be found that some of the small channels have been closed and the progress of the liquid stopped. When this fineness of particles is attained29, warmth sufficient to render the size quite fluid must be used, and the colour added gradually, stirring all the time with a rod. It may be here mentioned that where one colour only is required, vermilion is, perhaps, the best; and blue is seldom used for opaque30 objects, as it reflects very little more light than black.
12. When it is wished to fill the capillaries31 (the minute vessels connecting the arteries with the veins), the “Micrographic Dictionary” recommends the colouring matter to be made by double decomposition32. As a professed33 handbook would be, perhaps, deemed incomplete without some directions126 as to the mode of getting these colours, I will here make use of those given in that work. For red, however, vermilion, as above stated, may be used; but it must be carefully examined by reflected light to see whether it be free from all colourless crystals or not. It must first be worked in a mortar, and then the whole thrown into a quantity of water and stirred about; after leaving it not longer than a quarter of a minute, the larger portions will settle to the bottom, and the liquid being poured off will contain the finer powder. This may then be dried slowly, or added to the size whilst wet in the manner before advised.
13. Yellow injection.—To prepare this, take—
Acetate (sugar) of lead 380 grains.
Bichromate of potash 152 ”
Size    8 ounces.
Dissolve the lead salt in the warm size, then add the bichromate of potash finely powdered.
Some of the chromic acid remains34 free, and is wasted in this solution, so the following is given:—
Acetate of lead 190 grains.
Chromate of potash (neutral) 100 ”
Size    4 ounces.
The first of these has the deepest colour, and is the most generally used.
14. White injection.—This is a carbonate of lead:—
Acetate of lead 190 grains.
Carbonate of potash  83 ”
Size    4 ounces.
Dissolve the acetate of lead in the warm size, and filter through flannel; dissolve the carbonate of potash in the smallest quantity of water, and add to the size: 143 grains of carbonate of soda35 may be substituted for the carbonate of potash.
127 15. For blue injection, which is not, however, much used with reflected light, as before stated, take—
Prussian blue 73 grains.
Oxalic acid 73 ”
Size  4 ounces.
The oxalic acid is first finely powdered in a mortar, the Prussian blue and a little water added, and the whole then thoroughly mixed with the size.
16. It may here be repeated, that it is only when the capillaries are to be filled that there is any need to be at the trouble to prepare the colours by this double decomposition; and, indeed, colours ground so finely may be procured36 that the above instructions would have been omitted, had it not been supposed that some students might find a double pleasure in performing as much of the work as possible by their own unaided labours.
17. The process of injection may now be considered; but it is impossible for written instructions to supply the place of experience. I will do my best, however, to set the novice37 at least in the right way. There are two kinds of injection—one where the object and colours are opaque, and consequently fit for examination by reflected light only; the other, where the vessels are filled with transparent colours, and must be viewed by transmitted light. The first of these is most frequently employed, so we will begin with it. In the object which is to be injected a vessel of the kind which we wish to be filled must be found; an opening must then be made in it to allow one of the small pipes before mentioned to be thrust some distance within it. When this is accomplished, thread the curved needle with a piece of silk thread, or very fine string, which some operators rub well with beeswax. This thread must not be too thin, else there is danger of cutting the vessel. The cord is then carried under the inserted pipe, and the vessel bound tightly upon it, the ends being brought up round the transverse arms, and there tied; so that all danger of accidentally withdrawing128 the pipe is obviated39. Care must now be used in closing all the vessels which communicate with that where the pipe is placed lest the injecting fluid escape; and this must be done by tieing them with silk. Should, however, any of these be left open by accident, the bullnose forceps must be made use of, as before recommended.
18. The part to be injected must now be immersed in warm water, not, however, above 100° Fahrenheit40, and be left until the whole is thoroughly warmed. Whilst this is being done, the coloured size must be made ready by the pot being placed in the tin bath of warm water, which must be of sufficient temperature (about 110° Fahrenheit) to keep it perfectly liquid. For the same purpose, the syringe is often tightly covered with two or three folds of flannel; and, indeed, there is no part of the process which requires more attention. If the substance to be injected is too hot, it is injured; whilst, if any of the articles are too cold, the gelatine, or size, loses a part of its fluidity, and consequently cannot enter the minute parts. When all is prepared, the syringe, with the stopcock attached, should be warmed, and then filled and emptied with the injecting fluid two or three times, care being taken that the end of the syringe be kept beneath any bubbles which form upon the surface. The syringe may then be filled, and closely attached to the pipe which is tied in the vessel. With a firm and steady pressure the piston must be forced downwards41, when the substance will be perceived to swell42, and the colour show itself in places where the covering is thin. When the syringe is almost emptied of its contents, the stopcock must be turned to prevent any escape of the injection from the subject. It must then be refilled, as in the first instance, and the process repeated. I say almost emptied, because it is well not to force the piston of the syringe quite to the bottom, lest the small quantity of air which frequently remains be driven into some of the vessels, and the object be injured or quite ruined. As the injection is proceeded with, it will be found that the force required grows greater, yet care must be taken not to use129 too much, or the vessels will burst, and render all the labour fruitless. The movement of the piston must be occasionally so slow as to be almost imperceptible, and for this reason it is sometimes marked with lines about one-eighth of an inch apart.
19. Of course, during the whole process the injecting fluid and subject must be kept at a temperature high enough to allow the liquid to flow freely; and the escape of a little of it need cause no fears to the student, as it is almost impossible to fill any subject without some loss. When the injected object has received sufficient fluid, it should have a plump appearance, owing to all the vessels being well filled. The vessel must then be tied up where the pipe was inserted, and the whole left in cold water two or three hours, after which time it may be mounted; but it may be well to notice a few things which the beginner ought to know before entering into that part of the process; and he may be here informed that it is not necessary to mount the objects immediately, otherwise it would be impossible for one person to make use of half of any large subject, as it would be in a state of decay long before each part could have been examined and separated. Large pieces should be therefore immersed in equal parts of spirits of wine and water, or glycerine, which some think better still, and thus preserved in bottles until time can be given to a closer examination.
20. In operating upon large subjects, entire animals, &c., the constant pressure required by the piston of the syringe grows wearisome, besides occupying both hands, which is sometimes inconvenient43 when working without assistance. To obviate38 this, another way of driving the syringe was published in the “Micrographic Dictionary” which I will quote here:—“We have therefore contrived44 a very simple piece of apparatus, which any one can prepare for himself, and which effects the object by mechanical means. It consists of a rectangular piece of board, two feet long and ten inches wide, to one end of which is fastened an130 inclined piece of wood (equal in width to the long board, and one foot high). The inclined portion is pierced with three holes, one above the other, into either of which the syringe may be placed—the uppermost being used for the larger, the lowermost for the smaller syringe; and these holes are of such size as freely to admit the syringe covered with flannel, but not to allow the rings to pass through them. The lower part of the syringe is supported upon a semiannular piece of wood, fastened to the upper end of an upright rod, which slides in a hollow cylinder45 fixed11 at its base to a small rectangular piece of wood; and by means of a horizontal wooden screw, the rod may be made to support the syringe at any height required. The handle of the syringe is let into a groove46 in a stout47 wooden rod connected by means of two catgut strings48 with a smaller rod, to the middle of which is fastened a string playing over a pulley, and at the end of which is a hook for supporting weights, the catgut strings passing through a longitudinal slit49 in the inclined piece of wood.” When in use the syringe is filled with injecting fluid, and passed through one of the three holes which is most suitable. The object being placed so that the pipe and syringe can be best joined, the rod and strings are set in order, and a weight placed on the hook. The stopcock must then be opened gradually, when the operator will be able to judge whether the weight is a proper one or not: if the piston is driven with any speed, there is danger of injuring the subject, and less weight may be used; if, however, the piston does not move, more must be added.
21. Such is the method recommended by the “Micrographic Dictionary,” and perhaps it is as good as any mechanical plan could be; but where the operator is willing to undergo the labour of performing all this with the hand, he has a much better chance of succeeding, because the pressure can be regulated so accurately, and changed so quickly when requisite50, that no mere51 machine can compete with it, however well contrived.
131 22. When the beginner attempts to inject a subject, one of his difficulties is finding the vessel from which to commence. Another consists in distinguishing the arteries from the veins; but this is partly removed by making a longitudinal incision52 in the vessel, and with a blunt thick needle probing a little distance into the tube. The artery will be found thicker in the coating than the vein3, and the difference is easily perceived by this mode of testing: the vein is also of a bluer colour than the artery. I say above, a “longitudinal incision” must be made: the reason for this is, the artery when cut across contracts considerably53, and is lost in the adjoining substance; but where the opening is made longitudinally all danger of this contraction54 is obviated.
23. The different systems of vessels are often injected with various colours, so that their relative positions, &c., may be shown most clearly. In some specimens56, the veins are injected with white, and the arteries with red; in the kidney, the urinary tubes are often filled with white, and the arteries with red. Then, again, the liver affords tubes for three or four colours. But no written instructions on this point can benefit the young student, and he must be content for a while to employ himself with single colours until he has gained the mechanical skill and the primary knowledge which are necessary before he can make any advance.
24. We will now consider the best methods of mounting injected objects. They must always be well washed in water after they have been kept in any preservative57 liquid, using a camel-hair pencil to clean the surface if necessary. Many parts when injected are in masses, such as the lungs, liver, &c., of animals, and consequently sections of these must be cut. For this purpose Valentine’s knife is very convenient, as the thickness can be regulated so easily; but where the injections are opaque, there is no need to have the sections very thin. Some few of this kind undergo comparatively little change in drying, so that132 the section may be well washed and floated upon the glass slide in the place desired, where it will dry perfectly and adhere to it. It must be then moistened with turpentine and mounted in Canada balsam like other objects. No great heat should be used with these preparations, as it is very liable to injure them; and some of the colours seem to suffer a slight contraction when any great degree of warmth is applied58. There are many objects, however, which must be seen in the mass to be understood, and, indeed, lose all their form and beauty in drying, such as certain parts of the intestines59, &c. These must be mounted in fluid, with the precautions noticed at length in Chapter IV., and for this purpose either Goadby’s fluid, the chloride of zinc60 solution, or spirit diluted61 with ten parts of distilled62 water, may be employed. It is a good thing, when practicable, to mount similar objects on two separate slides, using different preservative liquids, and taking the precaution of marking each with the kind of liquid employed. This not only serves as a guide to what is best for certain subjects, but if one is injured, there will probably be a good specimen55 in the other.
25. It may be here mentioned that many are now mounting sections of injected substances with the balsam and chloroform before mentioned, instead of using balsam alone, and consider that the labour is much lessened63 thereby64.
26. A description of that mode of injection which is most generally employed has now been given, but this is not the only method of effecting our object. A most ingenious process was invented by M. Doyers, requiring no artificial warmth, by which many beautiful objects have been prepared. Make a solution of bichromate of potash, 524 grains to a pint65 of water, and throw this into the vessels to be injected; then take 1,000 grains of acetate of lead dissolved in half a pint of water, and force this into the same vessels. A decomposition now takes place in the vessels, and the yellow chromate of lead is formed. In this decomposition, however, the acetate of potash also is formed and as this133 salt has an injurious action upon the cells, Dr. Goadby recommends nitrate of lead to be used, which preserves rather than destroys them. He also advises the addition of two ounces of gelatine dissolved in eight ounces of water, to eight ounces of the saturated66 solution of each salt; but with this addition the hot-water bath would be required to keep the injecting fluid liquid.
27. Many of these are best mounted in balsam, in the same manner as those made in the ordinary way; whilst others are best shown when preserved in liquids, for which purpose Goadby’s fluid may be employed.
28. This mode of making injections with chromate of lead is deemed by many the best, especially where one colour only is employed. But it must be allowed that there is a little more danger of failure where two separate fluids are used for the same vessels.
29. We will now consider the best manner of making transparent injections, which, for many purposes, possess an undoubted advantage over the opaque ones. But it must be remembered that there are certain subjects to which no transparent injection could be applied, as they are too thick when in their natural state, and cutting would destroy all that beauty which is shown by the different parts in their relative adaptation. For those objects, however, which must be cut into sections to display their wonders, or are naturally thin—such as some of the finer tissues, livers, kidneys, &c.—transparency is a great acquisition, and enables us to understand the arrangement of the vessels more perfectly. Again, another advantage is the simplicity67 of the process; no hot water is needed with some preparations, either for the subject or the injecting fluid, which runs into the minute vessels thoroughly and easily, whilst the cost is small.
30. For this kind of injection no colour is so commonly made use of as Prussian blue. It is not a good one, as was before stated, for any opaque object, as the light reflected from it appears almost black; yet by transmitted134 light no colour is more useful, because its distinctness is equally great by artificial light and ordinary daylight. The method of preparing this, as given by Dr. Beale, is as follows:—
Glycerine  1 ounce.
Wood naphtha, or pyroacetic acid  1? drachm.
Spirits of wine  1 ounce.
Ferrocyanide (yellow prussiate) of potash 12 grains.
Tincture of sesquichloride of iron  1 drachm.
Water  4 ounces.
Dissolve the ferrocyanide of potash in one ounce of the water; add the tincture of sesquichloride of iron to another ounce. Mix these solutions gradually together, shaking the bottle well which contains them—it is best to add the iron to the potash solution. When thoroughly mixed, these solutions should produce a dark-blue mixture, perfectly free from any perceptible masses or flocculi. Next mix the naphtha and spirits of wine, and add the glycerine and the remaining two ounces of water. This must now be slowly mixed with the blue liquid, shaking the whole well in a large bottle whilst the two come together. The tincture of sesquichloride of iron is recommended, because it can always be obtained of a uniform strength.
31. Dr. Turnbull used a mixture slightly different from the above, which is made with the sulphate of iron:—
Purified sulphate of iron 10 grains.
Ferrocyanide of potassium 32 grains.
Glycerine  1 ounce.
Pyroacetic acid  1? drachm.
Alcohol  1 ounce.
Water  4 ounces.
Dissolve the sulphate of iron in one ounce of the water, gradually add the ferrocyanide of potassium dissolved in another ounce, and proceed as above.
135 32. Dr. Beale also gives us the following carmine68 injection to be employed in the same way as the blue.G Take—
Carmine 5 grains.
Glycerine, with 8 or 10 drops of hydrochloric acid ? ounce.
Glycerine (pure) 1 ounce.
Alcohol 2 drachms.
Water 6 drachms.
Mix the carmine with a few drops of water, and when well incorporated add about five drops of liquor ammoni?. To this dark-red solution about half an ounce of the glycerine is to be added, and the whole well shaken in a bottle. Next, very gradually pour in the acid glycerine, frequently shaking the bottle during admixture. Test the mixture with blue litmus-paper, and if not of a very decidedly acid reaction, a few more drops of acid may be added to the remainder of the glycerine and mixed as before. Lastly, mix the alcohol and water very gradually, shaking the bottle thoroughly after adding each successive portion till the whole is mixed. This fluid may be kept ready prepared, and injections made very rapidly with it.
G When, however, it is desirable to cut very thin sections of the injected subject, the carmine is sometimes added to a solution of fine gelatine—gelatine one part to water eight parts. But the warm water and mode of proceeding69 which are used with the size solutions before described will be necessary in this case also.
33. The method of making injections with these colours is the same as with the gelatine mixtures before described, except that no heat is required, and consequently most of the trouble removed. The bottle of the fluid must be well shaken immediately before use; and when the object is injected, we must allow it to remain in a cool place for a few hours before cutting it. Thin sections of the subject may be cut with Valentine’s knife, as before described, and are very beautiful transparent objects. Some of the finer tissues, also, are shown much better by this mode of injection136 than by the opaque, and are easily mounted by washing in clean water when first separated, and floating upon a slide, where they must be allowed to dry thoroughly. They may then be immediately mounted in balsam, or kept in the dry state until it is convenient to finish them; but in many cases this keeping, if too much prolonged, will injure the object. If it is desired to transfer the section to another slide, it will be necessary to wet it thoroughly with water by the aid of a camel-hair pencil, and then gently strip it off with the forceps. When it is wished to preserve injected subjects in “masses,” it must be done by immersion70 in spirit, and the sections may be cut at leisure. Most of these transparent objects may be mounted in Canada balsam; but some recommend glycerine or glycerine jelly, as allowing the use of a higher power in their examination, and preserving them in a more natural form.
34. A few subjects may be noticed which are very beautiful when injected, and amongst these are the eyes of many animals. They must be injected by the artery in the back part, and when the blue transparent liquid is employed, nothing can exceed the delicate beauty which some of the membrane71 bears. It must, however, be dissected72 with care, but well repays us for the trouble. Water-newts and frogs are not difficult subjects, and in their skin and other parts are many interesting objects. Amongst the commoner animals—rats, rabbits, cats, &c. &c.—almost endless employment may be found, making use either of portions or the whole animal at once. The intestines of many of these are very beautiful. We must divide them with a pair of scissors along the tube, and cleanse73 them from all the matter; the coating may then be laid upon a slide, and any remaining impurity74 removed with a camel-hair pencil and water. When dried it may be mounted in balsam, and having been injected with the transparent blue, its minute beauty is shown most perfectly. In injecting a sheep’s foot, which is a good137 object, the liquid should be forced into it until a slight paring of the hoof75 shows the colour in the fine channels there.
35. When the lungs of small animals are injected, the finest fluid must be used, as some of the capillaries are so small that it is not an easy matter to fill them properly. And before entering upon these subjects, a certain proficiency76 in the mode of using the syringe, &c., should be obtained by practising upon simpler parts.
36. No subjects are more difficult to inject than fish, owing to the extreme softness of their tissues. Dr. Hogg recommends the tail of the fish to be cut off, and the pipe to be put into the divided vessel which lies just beneath the spinal77 column; by which method beautiful injections may be made. The gills, however, are the most interesting part as microscopic78 objects.
37. These instructions may seem very imperfect to those who have had much experience in this branch; but they will remember that their own knowledge was not gained from any written descriptions, but was forced upon them by frequent failures, some of which probably were very disheartening. As I before stated, it is very difficult (if not impossible) to accomplish much without some knowledge of anatomy79.
38. I may here mention that the transparent injections sent over from the Continent are beautifully executed by Hyrtl of Vienna (who states that the injected fluid is composed of gelatine and carmine), Dr. Oschatz of Berlin, the Microscopic Institute of Wabern, Schaffer and Co. of Magdeburg, and others. Some of these will bear examining with a high power. A friend informs me that he measured a vessel in a rat’s tongue by Hyrtl, which was 1-7200th of an inch in diameter, and had a clear outline with quarter-inch objective. He has also made many experiments with the same materials, but has as yet failed in producing perfectly distinct outlines, there being a tendency of the colouring matter (magenta, carmine. &c.) to diffuse80 itself138 through the coats of the vessels into the surrounding tissues, although he has varied81 the pressure from one half a pound to sixty pounds. He believes the vessels are first washed out (injected with warm water and pressure applied), then some fluid introduced which renders the arteries impervious82 to the coloured fluid afterwards injected.
39. He finds that after washing out the vessels as above, the injecting fluid is much more easily introduced. He has used a strong solution of gallic acid previously83 to injecting with the colouring matter (in one experiment only), and the result was satisfactory. He puts the query,—Might not carbolic acid have a similar effect? He has often used it with injections to preserve the specimens, but not in sufficient quantity to act in the way indicated above.
Since writing the above, Mr. J. G. Dale, F.C.S., and I have made numerous experiments with carmine injection, and have at length been favoured with what we deem success. Some of the vessels in a kitten lately injected do not exceed 1-2000th of an inch in diameter, and present a clear outline with one-fifth objective. There is no extra-vasation, neither does the colouring matter show any grain except when a very high power is employed. The following is our process:—
Take 180 grains best carmine.
    ? fluid ounce of ammonia, commercial strength, viz., 0·92, or 15° ammonia meter.
     3 or 4 ounces distilled water.
Put these into a small flask84, and allow them to digest without heat from twenty-four to thirty-six hours, or until the carmine is dissolved. Then take a Winchester quart bottle, and with a diamond mark the spot to which sixteen ounces of water extend. The coloured solution must be filtered into the bottle, and to this pure water should be added until the whole is equal to sixteen ounces.
Dissolve 600 grains potash alum in ten fluid ounces of water, and add to this, under constant boiling, a solution139 of carbonate of soda until a slight permanent precipitate85 is produced. Filter and add water up to sixteen ounces. Boil and add the solution to the cold ammoniacal solution of carmine in the Winchester quart, and shake vigorously for a few minutes. A drop of this placed upon white filtering-paper should show no coloured ring. If much colour is in solution the whole must be rejected, because, although it is possible to precipitate all the colouring matter by the addition of ammonia or alum, it is not well to do so, as the physical condition of the precipitate is thereby altered.
Supposing the precipitation to be complete, or very nearly so, shake vigorously for at least half an hour, and allow it to stand until quite cold. The shaking must then be renewed for some time, and the bottle filled up with pure water.
After allowing the precipitate to settle a day, draw off the clear supernatant fluid with a syphon. Repeat the washing until the clear liquid gives little or no precipitate with chloride of barium. So much water must be left with the colour at last that it shall measure forty fluid ounces.
For the injecting fluid take twenty-four ounces of the above coloured liquid, and three ounces of good gelatine. Allow these to remain together twelve hours, and then dissolve by the heat of a water bath; after which it should be strained through fine muslin.
As this injecting fluid contains gelatine, the hot water, and other contrivances mentioned in a former part of the chapter, will be necessary here also, but no peculiar86 treatment will be required.

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1 arteries 821b60db0d5e4edc87fdf5fc263ba3f5     
n.动脉( artery的名词复数 );干线,要道
参考例句:
  • Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
  • This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》
2 veins 65827206226d9e2d78ea2bfe697c6329     
n.纹理;矿脉( vein的名词复数 );静脉;叶脉;纹理
参考例句:
  • The blood flows from the capillaries back into the veins. 血从毛细血管流回静脉。 来自《简明英汉词典》
  • I felt a pleasant glow in all my veins from the wine. 喝过酒后我浑身的血都热烘烘的,感到很舒服。 来自《简明英汉词典》
3 vein fi9w0     
n.血管,静脉;叶脉,纹理;情绪;vt.使成脉络
参考例句:
  • The girl is not in the vein for singing today.那女孩今天没有心情唱歌。
  • The doctor injects glucose into the patient's vein.医生把葡萄糖注射入病人的静脉。
4 vessels fc9307c2593b522954eadb3ee6c57480     
n.血管( vessel的名词复数 );船;容器;(具有特殊品质或接受特殊品质的)人
参考例句:
  • The river is navigable by vessels of up to 90 tons. 90 吨以下的船只可以从这条河通过。 来自《简明英汉词典》
  • All modern vessels of any size are fitted with radar installations. 所有现代化船只都有雷达装置。 来自《现代汉英综合大词典》
5 vessel 4L1zi     
n.船舶;容器,器皿;管,导管,血管
参考例句:
  • The vessel is fully loaded with cargo for Shanghai.这艘船满载货物驶往上海。
  • You should put the water into a vessel.你应该把水装入容器中。
6 apparatus ivTzx     
n.装置,器械;器具,设备
参考例句:
  • The school's audio apparatus includes films and records.学校的视听设备包括放映机和录音机。
  • They had a very refined apparatus.他们有一套非常精良的设备。
7 piston w2Rz7     
n.活塞
参考例句:
  • They use a piston engine instead.他们改用活塞发动机。
  • The piston moves by steam pressure.活塞在蒸汽压力下运动。
8 perfectly 8Mzxb     
adv.完美地,无可非议地,彻底地
参考例句:
  • The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
  • Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。
9 accurately oJHyf     
adv.准确地,精确地
参考例句:
  • It is hard to hit the ball accurately.准确地击中球很难。
  • Now scientists can forecast the weather accurately.现在科学家们能准确地预报天气。
10 affixed 0732dcfdc852b2620b9edaa452082857     
adj.[医]附着的,附着的v.附加( affix的过去式和过去分词 );粘贴;加以;盖(印章)
参考例句:
  • The label should be firmly affixed to the package. 这张标签应该牢牢地贴在包裹上。
  • He affixed the sign to the wall. 他将标记贴到墙上。 来自《简明英汉词典》
11 fixed JsKzzj     
adj.固定的,不变的,准备好的;(计算机)固定的
参考例句:
  • Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗?
  • Once the aim is fixed,we should not change it arbitrarily.目标一旦确定,我们就不应该随意改变。
12 artery 5ekyE     
n.干线,要道;动脉
参考例句:
  • We couldn't feel the changes in the blood pressure within the artery.我们无法感觉到动脉血管内血压的变化。
  • The aorta is the largest artery in the body.主动脉是人体中的最大动脉。
13 replenished 9f0ecb49d62f04f91bf08c0cab1081e5     
补充( replenish的过去式和过去分词 ); 重新装满
参考例句:
  • She replenished her wardrobe. 她添置了衣服。
  • She has replenished a leather [fur] coat recently. 她最近添置了一件皮袄。
14 situated JiYzBH     
adj.坐落在...的,处于某种境地的
参考例句:
  • The village is situated at the margin of a forest.村子位于森林的边缘。
  • She is awkwardly situated.她的处境困难。
15 bent QQ8yD     
n.爱好,癖好;adj.弯的;决心的,一心的
参考例句:
  • He was fully bent upon the project.他一心扑在这项计划上。
  • We bent over backward to help them.我们尽了最大努力帮助他们。
16 pointed Il8zB4     
adj.尖的,直截了当的
参考例句:
  • He gave me a very sharp pointed pencil.他给我一支削得非常尖的铅笔。
  • She wished to show Mrs.John Dashwood by this pointed invitation to her brother.她想通过对达茨伍德夫人提出直截了当的邀请向她的哥哥表示出来。
17 procure A1GzN     
vt.获得,取得,促成;vi.拉皮条
参考例句:
  • Can you procure some specimens for me?你能替我弄到一些标本吗?
  • I'll try my best to procure you that original French novel.我将尽全力给你搞到那本原版法国小说。
18 earthenware Lr5xL     
n.土器,陶器
参考例句:
  • She made sure that the glassware and earthenware were always spotlessly clean.她总是把玻璃器皿和陶器洗刷得干干净净。
  • They displayed some bowls of glazed earthenware.他们展出了一些上釉的陶碗。
19 sufficiently 0htzMB     
adv.足够地,充分地
参考例句:
  • It turned out he had not insured the house sufficiently.原来他没有给房屋投足保险。
  • The new policy was sufficiently elastic to accommodate both views.新政策充分灵活地适用两种观点。
20 cistern Uq3zq     
n.贮水池
参考例句:
  • The cistern is empty but soon fills again.蓄水池里现在没水,但不久就会储满水的。
  • The lavatory cistern overflowed.厕所水箱的水溢出来了
21 transparent Smhwx     
adj.明显的,无疑的;透明的
参考例句:
  • The water is so transparent that we can see the fishes swimming.水清澈透明,可以看到鱼儿游来游去。
  • The window glass is transparent.窗玻璃是透明的。
22 thoroughly sgmz0J     
adv.完全地,彻底地,十足地
参考例句:
  • The soil must be thoroughly turned over before planting.一定要先把土地深翻一遍再下种。
  • The soldiers have been thoroughly instructed in the care of their weapons.士兵们都系统地接受过保护武器的训练。
23 impurities 2626a6dbfe6f229f6e1c36f702812675     
不纯( impurity的名词复数 ); 不洁; 淫秽; 杂质
参考例句:
  • A filter will remove most impurities found in water. 过滤器会滤掉水中的大部分杂质。
  • Oil is refined to remove naturally occurring impurities. 油经过提炼去除天然存在的杂质。
24 flannel S7dyQ     
n.法兰绒;法兰绒衣服
参考例句:
  • She always wears a grey flannel trousers.她总是穿一条灰色法兰绒长裤。
  • She was looking luscious in a flannel shirt.她穿着法兰绒裙子,看上去楚楚动人。
25 counteracted 73400d69af35e4420879e17c972937fb     
对抗,抵消( counteract的过去式 )
参考例句:
  • This can be counteracted only by very effective insulation. 这只能用非常有效的绝缘来防止。
  • The effect of his preaching was counteracted by the looseness of his behavior. 他讲道的效果被他放荡的生活所抵消了。
26 accomplished UzwztZ     
adj.有才艺的;有造诣的;达到了的
参考例句:
  • Thanks to your help,we accomplished the task ahead of schedule.亏得你们帮忙,我们才提前完成了任务。
  • Removal of excess heat is accomplished by means of a radiator.通过散热器完成多余热量的排出。
27 distinguished wu9z3v     
adj.卓越的,杰出的,著名的
参考例句:
  • Elephants are distinguished from other animals by their long noses.大象以其长长的鼻子显示出与其他动物的不同。
  • A banquet was given in honor of the distinguished guests.宴会是为了向贵宾们致敬而举行的。
28 mortar 9EsxR     
n.灰浆,灰泥;迫击炮;v.把…用灰浆涂接合
参考例句:
  • The mason flushed the joint with mortar.泥工用灰浆把接缝处嵌平。
  • The sound of mortar fire seemed to be closing in.迫击炮的吼声似乎正在逼近。
29 attained 1f2c1bee274e81555decf78fe9b16b2f     
(通常经过努力)实现( attain的过去式和过去分词 ); 达到; 获得; 达到(某年龄、水平、状况)
参考例句:
  • She has attained the degree of Master of Arts. 她已获得文学硕士学位。
  • Lu Hsun attained a high position in the republic of letters. 鲁迅在文坛上获得崇高的地位。
30 opaque jvhy1     
adj.不透光的;不反光的,不传导的;晦涩的
参考例句:
  • The windows are of opaque glass.这些窗户装着不透明玻璃。
  • Their intentions remained opaque.他们的意图仍然令人费解。
31 capillaries d0d7ccc2f58ea09ec26e13a0d6ffd34a     
毛细管,毛细血管( capillary的名词复数 )
参考例句:
  • The blood flows from the capillaries back into the veins. 血从毛细血管流回静脉。
  • While Joe sleeps, a large percentage of his capillaries are inactive. 当乔睡觉时,他的毛细血管大部分是不工作的。
32 decomposition AnFzT     
n. 分解, 腐烂, 崩溃
参考例句:
  • It is said that the magnetite was formed by a chemical process called thermal decomposition. 据说这枚陨星是在热分解的化学过程中形成的。
  • The dehydration process leads to fairly extensive decomposition of the product. 脱水过程会导致产物相当程度的分解。
33 professed 7151fdd4a4d35a0f09eaf7f0f3faf295     
公开声称的,伪称的,已立誓信教的
参考例句:
  • These, at least, were their professed reasons for pulling out of the deal. 至少这些是他们自称退出这宗交易的理由。
  • Her manner professed a gaiety that she did not feel. 她的神态显出一种她并未实际感受到的快乐。
34 remains 1kMzTy     
n.剩余物,残留物;遗体,遗迹
参考例句:
  • He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
  • The remains of the meal were fed to the dog.残羹剩饭喂狗了。
35 soda cr3ye     
n.苏打水;汽水
参考例句:
  • She doesn't enjoy drinking chocolate soda.她不喜欢喝巧克力汽水。
  • I will freshen your drink with more soda and ice cubes.我给你的饮料重加一些苏打水和冰块。
36 procured 493ee52a2e975a52c94933bb12ecc52b     
v.(努力)取得, (设法)获得( procure的过去式和过去分词 );拉皮条
参考例句:
  • These cars are to be procured through open tender. 这些汽车要用公开招标的办法购买。 来自《现代汉英综合大词典》
  • A friend procured a position in the bank for my big brother. 一位朋友为我哥哥谋得了一个银行的职位。 来自《用法词典》
37 novice 1H4x1     
adj.新手的,生手的
参考例句:
  • As a novice writer,this is something I'm interested in.作为初涉写作的人,我对此很感兴趣。
  • She realized that she was a novice.她知道自己初出茅庐。
38 obviate 10Oy4     
v.除去,排除,避免,预防
参考例句:
  • Improved public transportation would obviate the need tor everyone to have their own car.公共交通的改善消除了每人都要有车的必要性。
  • This deferral would obviate pressure on the rouble exchange rate.这一延期将消除卢布汇率面临的压力。
39 obviated dc20674e61de9bd035f2495c16140204     
v.避免,消除(贫困、不方便等)( obviate的过去式和过去分词 )
参考例句:
40 Fahrenheit hlhx9     
n./adj.华氏温度;华氏温度计(的)
参考例句:
  • He was asked for the boiling point of water in Fahrenheit.他被问到水的沸点是华氏多少度。
  • The thermometer reads 80 degrees Fahrenheit.寒暑表指出华氏80度。
41 downwards MsDxU     
adj./adv.向下的(地),下行的(地)
参考例句:
  • He lay face downwards on his bed.他脸向下伏在床上。
  • As the river flows downwards,it widens.这条河愈到下游愈宽。
42 swell IHnzB     
vi.膨胀,肿胀;增长,增强
参考例句:
  • The waves had taken on a deep swell.海浪汹涌。
  • His injured wrist began to swell.他那受伤的手腕开始肿了。
43 inconvenient m4hy5     
adj.不方便的,令人感到麻烦的
参考例句:
  • You have come at a very inconvenient time.你来得最不适时。
  • Will it be inconvenient for him to attend that meeting?他参加那次会议会不方便吗?
44 contrived ivBzmO     
adj.不自然的,做作的;虚构的
参考例句:
  • There was nothing contrived or calculated about what he said.他说的话里没有任何蓄意捏造的成分。
  • The plot seems contrived.情节看起来不真实。
45 cylinder rngza     
n.圆筒,柱(面),汽缸
参考例句:
  • What's the volume of this cylinder?这个圆筒的体积有多少?
  • The cylinder is getting too much gas and not enough air.汽缸里汽油太多而空气不足。
46 groove JeqzD     
n.沟,槽;凹线,(刻出的)线条,习惯
参考例句:
  • They're happy to stay in the same old groove.他们乐于墨守成规。
  • The cupboard door slides open along the groove.食橱门沿槽移开。
48 strings nh0zBe     
n.弦
参考例句:
  • He sat on the bed,idly plucking the strings of his guitar.他坐在床上,随意地拨着吉他的弦。
  • She swept her fingers over the strings of the harp.她用手指划过竖琴的琴弦。
49 slit tE0yW     
n.狭长的切口;裂缝;vt.切开,撕裂
参考例句:
  • The coat has been slit in two places.这件外衣有两处裂开了。
  • He began to slit open each envelope.他开始裁开每个信封。
50 requisite 2W0xu     
adj.需要的,必不可少的;n.必需品
参考例句:
  • He hasn't got the requisite qualifications for the job.他不具备这工作所需的资格。
  • Food and air are requisite for life.食物和空气是生命的必需品。
51 mere rC1xE     
adj.纯粹的;仅仅,只不过
参考例句:
  • That is a mere repetition of what you said before.那不过是重复了你以前讲的话。
  • It's a mere waste of time waiting any longer.再等下去纯粹是浪费时间。
52 incision w4Dy7     
n.切口,切开
参考例句:
  • The surgeon made a small incision in the patient's cornea.外科医生在病人的眼角膜上切开一个小口。
  • The technique involves making a tiny incision in the skin.这项技术需要在皮肤上切一个小口。
53 considerably 0YWyQ     
adv.极大地;相当大地;在很大程度上
参考例句:
  • The economic situation has changed considerably.经济形势已发生了相当大的变化。
  • The gap has narrowed considerably.分歧大大缩小了。
54 contraction sn6yO     
n.缩略词,缩写式,害病
参考例句:
  • The contraction of this muscle raises the lower arm.肌肉的收缩使前臂抬起。
  • The forces of expansion are balanced by forces of contraction.扩张力和收缩力相互平衡。
55 specimen Xvtwm     
n.样本,标本
参考例句:
  • You'll need tweezers to hold up the specimen.你要用镊子来夹这标本。
  • This specimen is richly variegated in colour.这件标本上有很多颜色。
56 specimens 91fc365099a256001af897127174fcce     
n.样品( specimen的名词复数 );范例;(化验的)抽样;某种类型的人
参考例句:
  • Astronauts have brought back specimens of rock from the moon. 宇航员从月球带回了岩石标本。
  • The traveler brought back some specimens of the rocks from the mountains. 那位旅行者从山上带回了一些岩石标本。 来自《简明英汉词典》
57 preservative EQFxr     
n.防腐剂;防腐料;保护料;预防药
参考例句:
  • New timber should be treated with a preservative.新采的圆木应进行防腐处理。
  • Salt is a common food preservative.盐是一种常用的食物防腐剂。
58 applied Tz2zXA     
adj.应用的;v.应用,适用
参考例句:
  • She plans to take a course in applied linguistics.她打算学习应用语言学课程。
  • This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。
59 intestines e809cc608db249eaf1b13d564503dbca     
n.肠( intestine的名词复数 )
参考例句:
  • Perhaps the most serious problems occur in the stomach and intestines. 最严重的问题或许出现在胃和肠里。 来自辞典例句
  • The traps of carnivorous plants function a little like the stomachs and small intestines of animals. 食肉植物的捕蝇器起着动物的胃和小肠的作用。 来自辞典例句
60 zinc DfxwX     
n.锌;vt.在...上镀锌
参考例句:
  • Brass is formed by the fusion of copper and zinc.黄铜是通过铜和锌的熔合而成的。
  • Zinc is used to protect other metals from corrosion.锌被用来保护其他金属不受腐蚀。
61 diluted 016e8d268a5a89762de116a404413fef     
无力的,冲淡的
参考例句:
  • The paint can be diluted with water to make a lighter shade. 这颜料可用水稀释以使色度淡一些。
  • This pesticide is diluted with water and applied directly to the fields. 这种杀虫剂用水稀释后直接施用在田里。
62 distilled 4e59b94e0e02e468188de436f8158165     
adj.由蒸馏得来的v.蒸馏( distil的过去式和过去分词 );从…提取精华
参考例句:
  • The televised interview was distilled from 16 hours of film. 那次电视采访是从16个小时的影片中选出的精华。 来自《简明英汉词典》
  • Gasoline is distilled from crude oil. 汽油是从原油中提炼出来的。 来自《简明英汉词典》
63 lessened 6351a909991322c8a53dc9baa69dda6f     
减少的,减弱的
参考例句:
  • Listening to the speech through an interpreter lessened its impact somewhat. 演讲辞通过翻译的嘴说出来,多少削弱了演讲的力量。
  • The flight to suburbia lessened the number of middle-class families living within the city. 随着迁往郊外的风行,住在城内的中产家庭减少了。
64 thereby Sokwv     
adv.因此,从而
参考例句:
  • I have never been to that city,,ereby I don't know much about it.我从未去过那座城市,因此对它不怎么熟悉。
  • He became a British citizen,thereby gaining the right to vote.他成了英国公民,因而得到了投票权。
65 pint 1NNxL     
n.品脱
参考例句:
  • I'll have a pint of beer and a packet of crisps, please.我要一品脱啤酒和一袋炸马铃薯片。
  • In the old days you could get a pint of beer for a shilling.从前,花一先令就可以买到一品脱啤酒。
66 saturated qjEzG3     
a.饱和的,充满的
参考例句:
  • The continuous rain had saturated the soil. 连绵不断的雨把土地淋了个透。
  • a saturated solution of sodium chloride 氯化钠饱和溶液
67 simplicity Vryyv     
n.简单,简易;朴素;直率,单纯
参考例句:
  • She dressed with elegant simplicity.她穿着朴素高雅。
  • The beauty of this plan is its simplicity.简明扼要是这个计划的一大特点。
68 carmine eT1yH     
n.深红色,洋红色
参考例句:
  • The wind of the autumn color the maples carmine.秋风给枫林涂抹胭红。
  • The dish is fresh,fragrant,salty and sweet with the carmine color.这道菜用材新鲜,香甜入口,颜色殷红。
69 proceeding Vktzvu     
n.行动,进行,(pl.)会议录,学报
参考例句:
  • This train is now proceeding from Paris to London.这次列车从巴黎开往伦敦。
  • The work is proceeding briskly.工作很有生气地进展着。
70 immersion baIxf     
n.沉浸;专心
参考例句:
  • The dirt on the bottom of the bath didn't encourage total immersion.浴缸底有污垢,不宜全身浸泡于其中。
  • The wood had become swollen from prolonged immersion.因长时间浸泡,木头发胀了。
71 membrane H7ez8     
n.薄膜,膜皮,羊皮纸
参考例句:
  • A vibrating membrane in the ear helps to convey sounds to the brain.耳膜的振动帮助声音传送到大脑。
  • A plastic membrane serves as selective diffusion barrier.一层塑料薄膜起着选择性渗透屏障的作用。
72 dissected 462374bfe2039b4cdd8e07c3ee2faa29     
adj.切开的,分割的,(叶子)多裂的v.解剖(动物等)( dissect的过去式和过去分词 );仔细分析或研究
参考例句:
  • Her latest novel was dissected by the critics. 评论家对她最近出版的一部小说作了详细剖析。
  • He dissected the plan afterward to learn why it had failed. 他事后仔细剖析那项计划以便搞清它失败的原因。 来自《简明英汉词典》
73 cleanse 7VoyT     
vt.使清洁,使纯洁,清洗
参考例句:
  • Health experts are trying to cleanse the air in cities. 卫生专家们正设法净化城市里的空气。
  • Fresh fruit juices can also cleanse your body and reduce dark circles.新鲜果汁同样可以清洁你的身体,并对黑眼圈同样有抑制作用。
74 impurity b4Kye     
n.不洁,不纯,杂质
参考例句:
  • The oxygen reacts vigorously with the impurity in the iron.氧气与铁中的杂质发生剧烈的化学反应。
  • The more general impurity acid corrosion faster.一般来说杂质越多酸蚀速度越快。
75 hoof 55JyP     
n.(马,牛等的)蹄
参考例句:
  • Suddenly he heard the quick,short click of a horse's hoof behind him.突然间,他听见背后响起一阵急骤的马蹄的得得声。
  • I was kicked by a hoof.我被一只蹄子踢到了。
76 proficiency m1LzU     
n.精通,熟练,精练
参考例句:
  • He plied his trade and gained proficiency in it.他勤习手艺,技术渐渐达到了十分娴熟的地步。
  • How do you think of your proficiency in written and spoken English?你认为你的书面英语和口语熟练程度如何?
77 spinal KFczS     
adj.针的,尖刺的,尖刺状突起的;adj.脊骨的,脊髓的
参考例句:
  • After three days in Japan,the spinal column becomes extraordinarily flexible.在日本三天,就已经使脊椎骨变得富有弹性了。
  • Your spinal column is made up of 24 movable vertebrae.你的脊柱由24个活动的脊椎骨构成。
78 microscopic nDrxq     
adj.微小的,细微的,极小的,显微的
参考例句:
  • It's impossible to read his microscopic handwriting.不可能看清他那极小的书写字迹。
  • A plant's lungs are the microscopic pores in its leaves.植物的肺就是其叶片上微细的气孔。
79 anatomy Cwgzh     
n.解剖学,解剖;功能,结构,组织
参考例句:
  • He found out a great deal about the anatomy of animals.在动物解剖学方面,他有过许多发现。
  • The hurricane's anatomy was powerful and complex.对飓风的剖析是一项庞大而复杂的工作。
80 diffuse Al0zo     
v.扩散;传播;adj.冗长的;四散的,弥漫的
参考例句:
  • Direct light is better for reading than diffuse light.直射光比漫射光更有利于阅读。
  • His talk was so diffuse that I missed his point.他的谈话漫无边际,我抓不住他的要点。
81 varied giIw9     
adj.多样的,多变化的
参考例句:
  • The forms of art are many and varied.艺术的形式是多种多样的。
  • The hotel has a varied programme of nightly entertainment.宾馆有各种晚间娱乐活动。
82 impervious 2ynyU     
adj.不能渗透的,不能穿过的,不易伤害的
参考例句:
  • He was completely impervious to criticism.他对批评毫不在乎。
  • This material is impervious to gases and liquids.气体和液体都透不过这种物质。
83 previously bkzzzC     
adv.以前,先前(地)
参考例句:
  • The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • Let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
84 flask Egxz8     
n.瓶,火药筒,砂箱
参考例句:
  • There is some deposit in the bottom of the flask.这只烧杯的底部有些沉淀物。
  • He took out a metal flask from a canvas bag.他从帆布包里拿出一个金属瓶子。
85 precipitate 1Sfz6     
adj.突如其来的;vt.使突然发生;n.沉淀物
参考例句:
  • I don't think we should make precipitate decisions.我认为我们不应该贸然作出决定。
  • The king was too precipitate in declaring war.国王在宣战一事上过于轻率。
86 peculiar cinyo     
adj.古怪的,异常的;特殊的,特有的
参考例句:
  • He walks in a peculiar fashion.他走路的样子很奇特。
  • He looked at me with a very peculiar expression.他用一种很奇怪的表情看着我。


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