英国学生科学读本第66期:鸡蛋与小鸡(2)-英语课

时间：2019-01-17 作者：英语课 分类：英国学生科学读本

英语课

　　The shell is made of lime, and is very brittle 1. If you do not often give your hens some pieces of chalk or of lime to peck, they will very likely sometimes lay eggs without any shell at all.

　　蛋壳是石灰质的, 非常脆。如果你喂养的母鸡无法啄食到白垩或者石灰石, 有时候就很可能生下完全没有蛋壳的鸡蛋。
　　If you hold a fresh egg up to the light, you will see a small dark space just within the shell at the broad end of the egg. This space contains air. The egg-shell is lined with a thin skin, which is double at the broad end of the egg, and the air-space or air-chamber lies between the two layers of skin.
　　拿起一颗刚产下的鸡蛋, 对着灯光观察, 就会发现, 鸡蛋较宽一端的外壳下有一小块暗地方。那里包含的就是空气。蛋壳内部铺着一层薄膜, 鸡蛋较宽一端的薄膜有两层, 而气室就在这两层薄膜之间。
　　Next to this skin comes the "white, " which is a clear but somewhat yellowish liquid. In the middle of the egg is the yolk 2, which is coloured yellow by the oil or fat which it contains.
　　薄膜里面就是“蛋白”, 这是一种颜色有些发黄的清澈液体。鸡蛋中间则是蛋黄, 在油脂（也叫脂肪）的作用下, 蛋黄呈现出明亮的黄色。
　　This yolk is enclosed in a bag made of very thin skin. Prick 3 the yolk-bag, and the yellow stuff in it will run out very quickly. The yolk-bag is hung up, as it were, in the middle of the egg by means of two twisted whitish cords, which are fastened to the skin at each end of the shell.
　　蛋黄被包裹在一层非常薄的膜囊之中。如果戳破这层膜囊, 里面的蛋黄很快就会流出。在两条扭曲的白色索状组织作用下, 蛋黄膜囊悬挂在鸡蛋中间, 这两条索状组织固定在蛋壳两端的薄膜之上。
　　Sometimes we let the hens "sit" on some of their eggs to keep them warm. Then, after two days, a little chick will begin to form inside the egg, just on the top of the yolk. This chick will grow day by day. It will feed on the yolk and on the white, until after twenty-one days there will be neither white nor yolk left; but instead we shall have a perfect little chick, covered with small feathers. Then the chick pecks a hole in the shell and steps out, ready to wish you "good-morning. " Eggs can also be hatched without the help of the hens, by keeping them in warm boxes, or in a kind of oven which is warmed by hot water.
　　有时候, 我们让母鸡“坐在”蛋上面, 给蛋保暖。经过两天之后, 一只小鸡就会在鸡蛋之中展露雏形, 从蛋黄顶部开始发育。在随后的每一天里, 这只小鸡都会慢慢长大。蛋黄与蛋白都是这只小鸡的食物, 经过二十一天之后, 鸡蛋里面再也没有任何蛋黄或蛋白；取而代之的就是一只长满了小羽毛, 长大成形的小鸡。随后, 它就会在蛋壳上啄出一个小洞, 从洞中钻出, 准备向你问好。没有母鸡的话, 我们可以把鸡蛋放在暖箱或者通过热水加热的特制烘箱中, 从而孵化小鸡。
　　Most young birds are quite helpless when they leave the egg, and remain for some time in the nest, where they are fed by the parent birds. But the young chicks, and the young of several wild birds that build their nests on the ground, are able to run about and pick up their own food as soon as they are hatched.
　　大多数刚刚破壳而出的幼鸟都没有独立生存能力, 需要在鸟巢中生活一段时间, 依靠父母的喂食逐渐成长。然而, 小鸡和其他几种在地面上筑巢的野生鸟类的幼鸟, 在孵化之后, 便立刻能够奔跑和独立捕食。

英国学生科学读本 第66期:鸡蛋与小鸡(2)

英国学生科学读本第66期:鸡蛋与小鸡(2)