Chapter 17

Every animal in order to exist requires nutriment, in order to prevent itself from dying, refrigeration; and so Nature employs the same organ for both purposes. For, as in some cases the tongue serves both for discerning tastes and for speech, so in animals with lungs the mouth is employed both in working up the food and in the passage of the breath outwards¹ and inwards. In lungless and non-respiring animals it is employed in working up the food, while in those of them that require refrigeration it is the gills that are created for this purpose.

We shall state further on how it is that these organs have the faculty² of producing refrigeration. But to prevent their food from impeding³ these operations there is a similar contrivance in the respiring animals and in those that admit water. At the moment of respiration⁴ they do not take in food, for otherwise suffocation⁵ results owing to the food, whether liquid or dry, slipping in through the windpipe and lying on the lung. The windpipe is situated⁶ before the oesophagus, through which food passes into what is called the stomach, but in quadrupeds which are sanguineous there is, as it were, a lid over the windpipe-the epiglottis. In birds and oviparous quadrupeds this covering is absent, but its office is discharged by a contraction⁷ of the windpipe. The latter class contract the windpipe when swallowing their food; the former close down the epiglottis. When the food has passed, the epiglottis is in the one case raised, and in the other the windpipe is expanded, and the air enters to effect refrigeration. In animals with gills the water is first discharged through them and then the food passes in through the mouth; they have no windpipe and hence can take no harm from liquid lodging⁸ in this organ, only from its entering the stomach. For these reasons the expulsion of water and the seizing of their food is rapid, and their teeth are sharp and in almost all cases arranged in a saw-like fashion, for they are debarred from chewing their food.

1 outwards   

adj.外面的，公开的，向外的；adv.向外；n.外形

参考例句：

• Does this door open inwards or outwards?这门朝里开还是朝外开？
• In lapping up a fur,they always put the inner side outwards.卷毛皮时，他们总是让内层朝外。

2 faculty   

n.才能；学院，系；(学院或系的)全体教学人员

参考例句：

• He has a great faculty for learning foreign languages.他有学习外语的天赋。
• He has the faculty of saying the right thing at the right time.他有在恰当的时候说恰当的话的才智。

3 impeding   

a.(尤指坏事)即将发生的，临近的

参考例句：

• Fallen rock is impeding the progress of rescue workers. 坠落的石头阻滞了救援人员的救援进程。
• Is there sufficient room for the kiosk and kiosk traffic without impeding other user traffic? 该环境下是否有足够的空间来摆放信息亭？信息亭是否会妨碍交通或者行走？ 来自About Face 3交互设计精髓

4 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。

5 suffocation   

n.窒息

参考例句：

• The greatest dangers of pyroclastic avalanches are probably heat and suffocation. 火成碎屑崩落的最大危害可能是炽热和窒息作用。 来自辞典例句
• The room was hot to suffocation. 房间热得闷人。 来自辞典例句

6 situated   

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。

7 contraction   

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。

8 lodging   

n.寄宿，住所；(大学生的)校外宿舍

参考例句：

• The bill is inclusive of the food and lodging. 账单包括吃、住费用。
• Where can you find lodging for the night? 你今晚在哪里借宿?