You see your eyes were not meant to look at things so tiny as pollen grains. You can see a common ball or even a small shot very well indeed; but when it comes to pollen grains you are as blind as a mole. You will have to put on your spectacles to see _that_, I can tell you, and very powerful spectacles they will have to be, too. The best spectacles for you to look through are the ones we call a microscope. Just put your eye to that tube and you will see what you will see, for there are pollen grains at the other end—pollen grains from several kinds of flowers; there are some in the corner from our friend the morning-glory. And now you know what I meant when I said you could not see a pollen grain; for those little specks of dust have all at once become large and important objects. Some are round and some are not, and all are creased or pitted or ridged or covered with little points or marked in some other way. Now you see why they stick so easily to the hairs on the bee or the butterfly or whatever comes visiting the flowers for nectar. They are not smooth, but all roughened over by these ridges and points. And this is not the end of it. You have not yet seen a pollen grain. You have only seen the outside of one. For it has an inside. You think it is too small to have anything inside of it? I can tell you things _much_ smaller than that have something inside of them. The truth is, these things seem so small because we are so large. If we were as small as they, they would not seem small at all. They would seem a very ordinary size indeed, and we would expect them to have an outside and an inside. The truth is, pollen grains are hollow. They are as hollow as the baby’s rubber ball. But they are not _empty_. The baby’s rubber ball is not empty; it is full of air. These pollen grains are not full of air. If you were to see what is in them, you might not think it very important, but that would be a great mistake, for they are full of—protoplasm! The truth of the matter is, the pollen grain is a _cell_; it has a wall outside and is made of protoplasm inside. Protoplasm, you remember, is the material out of which every living thing is made. You are made from protoplasm yourself; flowers are made from it, too, and leaves and birds and _everything that lives_. So you see if a pollen grain is filled with protoplasm, that is rather a serious matter. This pollen grain, small as it is, has a tough outer skin. It is not as tough as leather, but it is tough for so small a grain, and is strong enough to keep the protoplasm from running out. The protoplasm in the pollen grain is what the ovule needs to nourish it and make it able to grow. The ovule, too, is a cell filled with protoplasm, and the protoplasm of the pollen and of the ovule must somehow come together before the ovule can do any more growing.