Book II Chapter 14

All animals that have hairs on the body have lashes¹ on the eyelids²; but birds and animals with scale-like plates, being hairless, have none. The Libyan ostrich³, indeed, forms an exception; for, though a bird, it is furnished with eyelashes. This exception, however, will be explained hereafter. Of hairy animals, man alone has lashes on both lids. For in quadrupeds there is a greater abundance of hair on the back than on the under side of the body; whereas in man the contrary is the case, and the hair is more abundant on the front surface than on the back. The reason for this is that hair is intended to serve as a protection to its possessor. Now, in quadrupeds, owing to their inclined attitude, the under or anterior⁴ surface does not require so much protection as the back, and is therefore left comparatively bald, in spite of its being the nobler of the two sides. But in man, owing to his upright attitude, the anterior and posterior surfaces of the body are on an equality as regards need of protection. Nature therefore has assigned the protective covering to the nobler of the two surfaces; for invariably she brings about the best arrangement of such as are possible. This then is the reason that there is no lower eyelash in any quadruped; though in some a few scattered⁵ hairs sprout⁶ out under the lower lid. This also is the reason that they never have hair in the axillae, nor on the pubes, as man has. Their hair, then, instead of being collected in these parts, is either thickly set over the whole dorsal⁷ surface, as is the case for instance in dogs, or, sometimes, forms a mane, as in horses and the like, or as in the male lion where the mane is still more flowing and ample. So, again, whenever there is a tail of any length, nature decks it with hair, with long hair if the stem of the tail be short, as in horses, with short hair if the stem be long, regard also being had to the condition of the rest of the body. For nature invariably gives to one part what she subtracts from another. Thus when she has covered the general surface of an animal’s body with an excess of hair, she leaves a deficiency in the region of the tail. This, for instance, in the case with bears.

No animal has so much hair on the head as man. This, in the first place, is the necessary result of the fluid character of his brain, and of the presence of so many sutures in his skull⁸. For wherever there is the most fluid and the most heat, there also must necessarily occur the greatest outgrowth. But, secondly⁹, the thickness of the hair in this part has a final cause, being intended to protect the head, by preserving it from excess of either heat or cold. And as the brain of man is larger and more fluid than that of any other animal, it requires a proportionately greater amount of protection. For the more fluid a substance is, the more readily does it get excessively heated or excessively chilled, while substances of an opposite character are less liable to such injurious affections.

These, however, are matters which by their close connexion with eyelashes have led us to digress from our real topic, namely the cause to which these lashes owe their existence. We must therefore defer¹⁰ any further remarks we may have to make on these matters till the proper occasion arises and then return to their consideration.

1 lashes   

n.鞭挞( lash的名词复数 )；鞭子；突然猛烈的一击；急速挥动v.鞭打( lash的第三人称单数 )；煽动；紧系；怒斥

参考例句：

• Mother always lashes out food for the children's party. 孩子们聚会时，母亲总是给他们许多吃的。 来自《简明英汉词典》
• Never walk behind a horse in case it lashes out. 绝对不要跟在马后面，以防它突然猛踢。 来自《简明英汉词典》

2 eyelids   

n.眼睑( eyelid的名词复数 )；眼睛也不眨一下；不露声色；面不改色

参考例句：

• She was so tired, her eyelids were beginning to droop. 她太疲倦了，眼睑开始往下垂。
• Her eyelids drooped as if she were on the verge of sleep. 她眼睑低垂好像快要睡着的样子。 来自《简明英汉词典》

3 ostrich   

n.鸵鸟

参考例句：

• Ostrich is the fastest animal on two legs.驼鸟是双腿跑得最快的动物。
• The ostrich indeed inhabits continents.鸵鸟确实是生活在大陆上的。

4 anterior   

adj.较早的；在前的

参考例句：

• We've already finished the work anterior to the schedule.我们已经提前完成了工作。
• The anterior part of a fish contains the head and gills.鱼的前部包括头和鳃。

5 scattered   

adj.分散的，稀疏的；散步的；疏疏落落的

参考例句：

• Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来，塞进文件夹里。

6 sprout   

n.芽，萌芽；vt.使发芽，摘去芽；vi.长芽，抽条

参考例句：

• When do deer first sprout horns?鹿在多大的时候开始长出角？
• It takes about a week for the seeds to sprout.这些种子大约要一周后才会发芽。

7 dorsal   

adj.背部的，背脊的

参考例句：

• His dorsal fin was down and his huge pectorals were spread wide.它的脊鳍朝下耷拉着，巨大的胸鳍大张着。
• The shark's dorsal fin was cut off by the fisherman.鲨鱼的背鳍被渔夫割了下来。

8 skull   

n.头骨；颅骨

参考例句：

• The skull bones fuse between the ages of fifteen and twenty-five.头骨在15至25岁之间长合。
• He fell out of the window and cracked his skull.他从窗子摔了出去，跌裂了颅骨。

9 secondly   

adv.第二，其次

参考例句：

• Secondly,use your own head and present your point of view.第二，动脑筋提出自己的见解。
• Secondly it is necessary to define the applied load.其次，需要确定所作用的载荷。

10 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。