The following stages are even more interesting, especially for those who can take advantage of the transparency of the parts to watch the circulation of the blood through a microscope. The body of the tadpole gradually gets broader, while the tail gets thinner and thinner, till it finally disappears altogether; but before that happens its place has been taken by two hind legs, which first appear under the skin and then gradually push their way through. The fore legs next appear, and so on through all the stages of development, till in a longer or shorter time, according to the amount of warmth, light, and food it can obtain, the complete frog appears. But woe betide the unfortunate tadpole which, first of the shoal, attains to the dignity of possessing limbs, for so ferocious are the later ones, and so jealous of their precocious little brother, that they almost always fall upon him, and, not content with killing, never rest till every morsel of him is eaten. And unless several of the tadpoles assume their final change about the same time, this proceeding is repeated till their numbers are very considerably diminished, or, as sometimes happens, till only one survivor is left, who, having helped to eat all his brethren, instead of meeting with his deserts, is allowed to live on in peace, till some day in the course of his walks abroad, he, in his turn, is snapped up as a delicate morsel by some hungry snake or waterfowl. Insects and flowers are much more closely connected with one another than we sometimes think. Not only do many insects depend upon flowers for their food, but many flowers also depend upon the visits of insects to carry their pollen from one flower to another and so continue the life of their species. There are some flowers, however, whose pollen is carried by the wind instead of by insects, and which are therefore an exception to this general rule. These, not needing to attract insects, are small and insignificant, with neither scent nor honey, but with a very large quantity of pollen. They generally flower early in spring, before the leaves are out, as these would catch the pollen as it is blown along by the wind, and prevent it reaching the flowers for which it is intended. Notice, for example, the flower of the oak, elm, ash, and Scotch fir. April is a busy month in the garden. Auriculas and polyanthuses in bloom should be watered often, and shaded if the sun is very bright, and sheltered when the weather is cold; tulips also must be sheltered from severe cold, though they may safely be encouraged to grow now.