Book III chapter 6

The lung, then, is an organ found in all the animals of a certain class, because they live on land. For there must of necessity be some means or other of tempering the heat of the body; and in sanguineous animals, as they are of an especially hot nature, the cooling agency must be external, whereas in the bloodless kinds the innate¹ spirit is sufficient of itself for the purpose. The external cooling agent must be either air or water. In fishes the agent is water. Fishes therefore never have a lung, but have gills in its place, as was stated in the treatise² on Respiration³. But animals that breathe are cooled by air. These therefore are all provided with a lung.

All land animals breathe, and even some water animals, such as the whale, the dolphin, and all the spouting⁴ Cetacea. For many animals lie half-way between terrestrial and aquatic⁵; some that are terrestrial and that inspire air being nevertheless of such a bodily constitution that they abide⁶ for the most time in the water; and some that are aquatic partaking so largely of the land character, that respiration constitutes for them the man condition of life.

The organ of respiration is the lung. This derives⁷ its motion from the heart; but it is its own large size and spongy texture⁸ that affords amplitude⁹ of space for entrance of the breath. For when the lung rises up the breath streams in, and is again expelled when the lung collapses¹⁰. It has been said that the lung exists as a provision to meet the jumping of the heart. But this is out of the question. For man is practically the only animal whose heart presents this phenomenon of jumping, inasmuch as he alone is influenced by hope and anticipation¹¹ of the future. Moreover, in most animals the lung is separated from the heart by a considerable interval¹² and lies above it, so that it can contribute nothing to mitigate¹³ any jumping.

The lung differs much in different animals. For in some it is of large size and contains blood; while in others it is smaller and of spongy texture. In the vivipara it is large and rich in blood, because of their natural heat; while in the ovipara it is small and dry but capable of expanding to a vast extent when inflated¹⁴. Among terrestrial animals, the oviparous quadrupeds, such as lizards¹⁵, tortoises, and the like, have this kind of lung; and, among inhabitants of the air, the animals known as birds. For in all these the lung is spongy, and like foam¹⁶. For it is membranous¹⁷ and collapses from a large bulk to a small one, as does foam when it runs together. In this too lies the explanation of the fact that these animals are little liable to thirst and drink but sparingly, and that they are able to remain for a considerable time under water. For, inasmuch as they have but little heat, the very motion of the lung, airlike and void, suffices by itself to cool them for a considerable period.

These animals, speaking generally, are also distinguished¹⁸ from others by their smaller bulk. For heat promotes growth, and abundance of blood is a sure indication of heat. Heat, again, tends to make the body erect¹⁹; and thus it is that man is the most erect of animals, and the vivipara more erect than other quadrupeds. For no viviparous animal, be it apodous or be it possessed²⁰ of feet, is so given to creep into holes as are the ovipara.

The lung, then, exists for respiration; and this is its universal office; but in one order of animals it is bloodless and has the structure described above, to suit the special requirements There is, however, no one term to denote all animals that have a lung; no designation, that is, like the term Bird, applicable to the whole of a certain class. Yet the possession of a lung is a part of their essence, just as much as the presence of certain characters constitutes the essence of a bird.

1 innate   

adj.天生的，固有的，天赋的

参考例句：

• You obviously have an innate talent for music.你显然有天生的音乐才能。
• Correct ideas are not innate in the mind.人的正确思想不是自己头脑中固有的。

2 treatise   

n.专著；(专题)论文

参考例句：

• The doctor wrote a treatise on alcoholism.那位医生写了一篇关于酗酒问题的论文。
• This is not a treatise on statistical theory.这不是一篇有关统计理论的论文。

3 respiration   

n.呼吸作用；一次呼吸；植物光合作用

参考例句：

• They tried artificial respiration but it was of no avail.他们试做人工呼吸，可是无效。
• They made frequent checks on his respiration,pulse and blood.他们经常检查他的呼吸、脉搏和血液。

4 spouting   

n.水落管系统v.（指液体）喷出( spout的现在分词 )；滔滔不绝地讲；喋喋不休地说；喷水

参考例句：

• He's always spouting off about the behaviour of young people today. 他总是没完没了地数落如今年轻人的行为。 来自《简明英汉词典》
• Blood was spouting from the deep cut in his arm. 血从他胳膊上深深的伤口里涌出来。 来自《简明英汉词典》

5 aquatic   

adj.水生的，水栖的

参考例句：

• Aquatic sports include swimming and rowing.水上运动包括游泳和划船。
• We visited an aquatic city in Italy.我们在意大利访问过一个水上城市。

6 abide   

vi.遵守；坚持；vt.忍受

参考例句：

• You must abide by the results of your mistakes.你必须承担你的错误所造成的后果。
• If you join the club,you have to abide by its rules.如果你参加俱乐部，你就得遵守它的规章。

7 derives   

v.得到( derive的第三人称单数 )；（从…中）得到获得；源于；（从…中）提取

参考例句：

• English derives in the main from the common Germanic stock. 英语主要源于日耳曼语系。 来自《简明英汉词典》
• He derives his income from freelance work. 他以自由职业获取收入。 来自《简明英汉词典》

8 texture   

n.(织物)质地；(材料)构造；结构；肌理

参考例句：

• We could feel the smooth texture of silk.我们能感觉出丝绸的光滑质地。
• Her skin has a fine texture.她的皮肤细腻。

9 amplitude   

n.广大；充足；振幅

参考例句：

• The amplitude of the vibration determines the loudness of the sound.振动幅度的大小决定声音的大小。
• The amplitude at the driven end is fixed by the driving mechanism.由于驱动机构的作用,使驱动端的振幅保持不变。

10 collapses   

折叠( collapse的第三人称单数 )； 倒塌； 崩溃； （尤指工作劳累后）坐下

参考例句：

• This bridge table collapses. 这张桥牌桌子能折叠。
• Once Russia collapses, the last chance to stop Hitler will be gone. 一旦俄国垮台，抑止希特勒的最后机会就没有了。

11 anticipation   

n.预期，预料，期望

参考例句：

• We waited at the station in anticipation of her arrival.我们在车站等着，期待她的到来。
• The animals grew restless as if in anticipation of an earthquake.各种动物都变得焦躁不安，像是感到了地震即将发生。

12 interval   

n.间隔，间距；幕间休息，中场休息

参考例句：

• The interval between the two trees measures 40 feet.这两棵树的间隔是40英尺。
• There was a long interval before he anwsered the telephone.隔了好久他才回了电话。

13 mitigate   

vt.（使）减轻，（使）缓和

参考例句：

• The government is trying to mitigate the effects of inflation.政府正试图缓和通货膨胀的影响。
• Governments should endeavour to mitigate distress.政府应努力缓解贫困问题。

14 inflated   

adj.（价格）飞涨的；（通货）膨胀的；言过其实的；充了气的v.使充气（于轮胎、气球等）( inflate的过去式和过去分词 )；（使）膨胀；（使）通货膨胀；物价上涨

参考例句：

• He has an inflated sense of his own importance. 他自视过高。
• They all seem to take an inflated view of their collective identity. 他们对自己的集体身份似乎都持有一种夸大的看法。 来自《简明英汉词典》

15 lizards   

n.蜥蜴( lizard的名词复数 )

参考例句：

• Nothing lives in Pompeii except crickets and beetles and lizards. 在庞培城里除了蟋蟀、甲壳虫和蜥蜴外，没有别的生物。 来自辞典例句
• Can lizards reproduce their tails? 蜥蜴的尾巴断了以后能再生吗？ 来自辞典例句

16 foam   

v./n.泡沫，起泡沫

参考例句：

• The glass of beer was mostly foam.这杯啤酒大部分是泡沫。
• The surface of the water is full of foam.水面都是泡沫。

17 membranous   

adj.膜的，膜状的

参考例句：

• Others are born live, after struggling to break free from a membranous egg sac. 其余的是冲破膜状蛋囊而出生的。 来自电影对白
• Thellos thellon, membranous layer of life is our only home. 薄薄的膜层就是咱们独一的家园。 来自互联网

18 distinguished   

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。

19 erect   

n./v.树立，建立，使竖立；adj.直立的，垂直的

参考例句：

• She held her head erect and her back straight.她昂着头，把背挺得笔直。
• Soldiers are trained to stand erect.士兵们训练站得笔直。

20 possessed   

adj.疯狂的；拥有的，占有的

参考例句：

• He flew out of the room like a man possessed.他像着了魔似地猛然冲出房门。
• He behaved like someone possessed.他行为举止像是魔怔了。