Book IV chapter 4

The so-called mesentery is also a membrane¹; and extends continuously from the long stretch of intestine² to the great vessel³ and the aorta⁴. In it are numerous and close-packed vessels⁵, which run from the intestines⁶ to the great vessel and to the aorta. The formation of this membrane we shall find to be the result of necessity, as is that of the other [similar] parts. What, however, is the final cause of its existence in sanguineous animals is manifest on reflection. For it is necessary that animals shall get nutriment from without; and, again, that this shall be converted into the ultimate nutriment, which is then distributed as sustenance⁷ to the various parts; this ultimate nutriment being, in sanguineous animals, what we call blood, and having, in bloodless animals, no definite name. This being so, there must be channels through which the nutriment shall pass, as it were through roots, from the stomach into the blood-vessels. Now the roots of plants are in the ground; for thence their nutriment is derived⁸. But in animals the stomach and intestines represent the ground from which the nutriment is to be taken. The mesentery, then, is an organ to contain the roots; and these roots are the vessels that traverse it. This then is the final cause of its existence. But how it absorbs nutriment, and how that portion of the food which enters into the vessels is distributed by them to the various parts of the body, are questions which will be considered when we come to deal with the generation and nutrition of animals.

The constitution of sanguineous animals, so far as the parts as yet mentioned are concerned, and the reasons for such constitution, have now been set forth⁹. In natural sequence we should next go on to the organs of generation, as yet undescribed, on which depend the distinctions of male and female. But, inasmuch as we shall have to deal specially¹⁰ with generation hereafter, it will be more convenient to defer¹¹ the consideration of these parts to that occasion.

1 membrane   

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。

2 intestine   

adj.内部的；国内的；n.肠

参考例句：

• This vitamin is absorbed through the walls of the small intestine.这种维生素通过小肠壁被吸收。
• The service productivity is the function,including external efficiency,intestine efficiency and capacity efficiency.服务业的生产率是一个包含有外部效率、内部效率和能力效率的函数。

3 vessel   

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。

4 aorta   

n.主动脉

参考例句：

• The abdominal aorta is normally smaller than the thoracic aorta.腹主动脉一般比胸主动脉小。
• Put down that jelly doughnut and look carefully at this aorta.放下手头上的东西，认真观察这张大动脉图片。

5 vessels   

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》

6 intestines   

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

7 sustenance   

n.食物，粮食；生活资料；生计

参考例句：

• We derive our sustenance from the land.我们从土地获取食物。
• The urban homeless are often in desperate need of sustenance.城市里无家可归的人极其需要食物来维持生命。

8 derived   

vi.起源；由来；衍生；导出v.得到( derive的过去式和过去分词 )；（从…中）得到获得；源于；（从…中）提取

参考例句：

• Many English words are derived from Latin and Greek. 英语很多词源出于拉丁文和希腊文。 来自《简明英汉词典》
• He derived his enthusiasm for literature from his father. 他对文学的爱好是受他父亲的影响。 来自《简明英汉词典》

9 forth   

adv.向前；向外，往外

参考例句：

• The wind moved the trees gently back and forth.风吹得树轻轻地来回摇晃。
• He gave forth a series of works in rapid succession.他很快连续发表了一系列的作品。

10 specially   

adv.特定地；特殊地；明确地

参考例句：

• They are specially packaged so that they stack easily.它们经过特别包装以便于堆放。
• The machine was designed specially for demolishing old buildings.这种机器是专为拆毁旧楼房而设计的。

11 defer   

vt.推迟，拖延；vi.(to)遵从，听从，服从

参考例句：

• We wish to defer our decision until next week.我们希望推迟到下星期再作出决定。
• We will defer to whatever the committee decides.我们遵从委员会作出的任何决定。