英文科学读本 第三册·Lesson 31 The Frog—Its Life History

Lesson 31 The Frog—Its Life History

Suppose my frog could talk, Norah, would you like him to tell you his history?

I should like it very much, said Norah.

Then just shut your eyes and imagine me to be the frog. Listen to my story.

I have not much to thank my mother for. The first thing I remember was that I was a tiny thing, with a big head and a long, flat, waving tail. I found myself swimming about in the water. I had just come out of an egg, which my mother had laid in the water. In fact, that's all I know about my mother, for, as I told you, I never had a mother's care. People called me a tadpole.

Well, there I found myself, and I couldn't make out what I was. I was not a fish, although I had gills for breathing in the water, just as fishes have.

Presently I began to feel hungry, and it seemed quite natural for me to go to the water-plants and nibble off the soft shoots. I did not wish for any other food, and my mouth seemed made on purpose for this, for it was placed not in front of my head, but under my chin, if you can make that out.

It was not a bad sort of life on the whole. I enjoyed myself very well, but I had to be always dodging the big hungry fishes, who wanted to make a meal of me.

Well, this sort of thing went on for about six or eight weeks, when one day I began to be very frightened. I thought I must be growing deformed in some way, for I found two humps forming, one on each side of my tail.

Day by day these humps grew, and presently two others began to show just behind my head.

This was alarming, but it was nothing compared with my horror at finding that my beautiful waving tail was shrinking and wasting away by degrees,

Day by day I swam about trying to make the best of it, when at last my tail went altogether. It dropped off.

But by this time those humps at the sides of it had formed into a pair of beautiful long legs, and feet with webbed toes, just made for swimming. The other humps in front, too, had grown into another pair of legs, so that I found myself with four limbs, just as you see me now.

My head and body had also grown larger and broader. Besides this, as my head took a more respectable, frog-like shape, my mouth became large and broad, and changed places to the front of my head, where it is now.

Two things then happened. First I went quite off my appetite; that is to say, I couldn't eat those green shoots of the water-plants any longer. I seemed to have a craving for animal food.

At the same time I felt that I was being stifled. My gills had wasted away entirely, and now I could no longer breathe in the water. Something—I can't tell what it was—prompted me to leave the water, and as soon as I got on the bank by the pond, I found I could breathe air, for I had lungs instead of gills.

Just then a small beetle ran past me. I was only a very little fellow then, but I pounced upon it like lightning, and swallowed it in a moment.

I never felt so savage before, but I've made many a good meal since then on grubs, insects, worms, and slugs.

As I grew larger and larger my skin from time to time split, and I always tore it off with my paws, and swallowed it every bit. There was each time a new one underneath to fit me.'

SUMMARY

The frog comes from an egg laid by its parent at the bottom of the water. The egg rises to the surface, and is hatched by the heat of the sun. It begins life as a tadpole, with no limbs; it breathes by means of gills, like a fish, and feeds upon the green shoots of the water-plants. It passes through various stages, and undergoes many changes for about six or eight weeks. At the end of that time it leaves the water as a fully-developed frog, with lungs, not gills; with four limbs, but no tail; and with even its feeding instincts changed. The frog feeds upon worms, grubs, and insects.