英國學(xué)生科學(xué)讀本 Lesson 66 雞蛋與小雞(2)

The shell is made of lime, and is very brittle. 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.

蛋殼是石灰質(zhì)的, 非常脆。如果你喂養(yǎng)的母雞無法啄食到白堊或者石灰石, 有時候就很可能生下完全沒有蛋殼的雞蛋。

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.

拿起一顆剛產(chǎn)下的雞蛋, 對著燈光觀察, 就會發(fā)現(xiàn), 雞蛋較寬一端的外殼下有一小塊暗地方。那里包含的就是空氣。蛋殼內(nèi)部鋪著一層薄膜, 雞蛋較寬一端的薄膜有兩層, 而氣室就在這兩層薄膜之間。

Next to this skin comes the "white, " which is a clear but somewhat yellowish liquid. In the middle of the egg is the yolk, which is coloured yellow by the oil or fat which it contains.

薄膜里面就是“蛋白”, 這是一種顏色有些發(fā)黃的清澈液體。雞蛋中間則是蛋黃, 在油脂(也叫脂肪)的作用下, 蛋黃呈現(xiàn)出明亮的黃色。

This yolk is enclosed in a bag made of very thin skin. Prick 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.

蛋黃被包裹在一層非常薄的膜囊之中。如果戳破這層膜囊, 里面的蛋黃很快就會流出。在兩條扭曲的白色索狀組織作用下, 蛋黃膜囊懸掛在雞蛋中間, 這兩條索狀組織固定在蛋殼兩端的薄膜之上。

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.

有時候, 我們讓母雞“坐在”蛋上面, 給蛋保暖。經(jīng)過兩天之后, 一只小雞就會在雞蛋之中展露雛形, 從蛋黃頂部開始發(fā)育。在隨后的每一天里, 這只小雞都會慢慢長大。蛋黃與蛋白都是這只小雞的食物, 經(jīng)過二十一天之后, 雞蛋里面再也沒有任何蛋黃或蛋白;取而代之的就是一只長滿了小羽毛, 長大成形的小雞。隨后, 它就會在蛋殼上啄出一個小洞, 從洞中鉆出, 準備向你問好。沒有母雞的話, 我們可以把雞蛋放在暖箱或者通過熱水加熱的特制烘箱中, 從而孵化小雞。

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.

大多數(shù)剛剛破殼而出的幼鳥都沒有獨立生存能力, 需要在鳥巢中生活一段時間, 依靠父母的喂食逐漸成長。然而, 小雞和其他幾種在地面上筑巢的野生鳥類的幼鳥, 在孵化之后, 便立刻能夠奔跑和獨立捕食。

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