Look at No. 1 and No. 2 (Fig. 43) and you will see at once that if an insect goes into No. 1 and the pollen sticks to him, when he goes into No. 2 just that part of his body on which the pollen is will touch the knob; and so the flowers become what we call “crossed,” that is, the pollen-dust of the one feeds the ovule of the other.  And just the same thing will happen if he flies from No. 2 to No. 1.  There the dust will be just in the position to touch the knob which sticks out of the flower.

Therefore, we can see clearly that it is good for the primrose that bees and other insects should come to it, and anything it can do to entice them will be useful.  Now, do you not think that when an insect once knew that the pale-yellow crown showed where honey was to be found, he would soon spy these crowns out as he flew along? or if they were behind a hedge, and he could not see them, would not the sweet scent tell him where to come and look for them?  And so we see that the pretty sweet-scented corolla is not only delightful for us to look at and to smell, but it is really very useful in helping the primrose to make strong healthy seeds out of which the young plants are to grow next year.

And now let us see what we have learnt.  We began with a tiny seed, though we did not then know how this seed had been made.  We saw the plantlet buried in it, and learnt how it fed at first on prepared food, but soon began to make living matter for itself out of gases taken from the water through the cells to its stomach — the leaves!  And how marvellously the sun-waves entering there formed the little green granules, and then helped them to make food and living protoplasm!  At this point we might have gone further, and studied how the fibres and all the different vessels of the plant are formed, and a wondrous history it would have been.  But it was too long for one hour’s lecture, and you must read it for yourselves in books on botany.  We had to pass on to the flower, and learn the use of the covering leaves, the gaily coloured crown attracting the insects, the dust-bags holding the pollen, the little ovules each with the germ of a new plantlet, lying hidden in the seed- vessel, waiting for the pollen-grains to grow down to them.  Lastly, when the pollen crept in at the tiny opening we learnt that the ovule had now all it wanted to grow into a perfect seed.

And so we came back to a primrose seed, the point from which we started; and we have a history of our primrose from its birth to the day when its leaves and flowers wither away and it dies down for the winter.

But what fairies are they which have been at work here?  First, the busy little fairy Life in the active protoplasm; and secondly, the sun-waves.  We have seen that it was by the help of the sunbeams that the green granules were made, and the water, carbonic acid, and nitrogen worked up into the living plant.  And in doing this work the sun-waves were caught and their strength used up, so that they could no longer quiver back into space.  But are they gone for ever?  So long as the leaves or the stem or the root of the plant remain they are gone, but when those are destroyed we can get them back again.  Take a handful of dry withered plants and light them with a match, then as the leaves burn and are turned back again to carbonic acid, nitrogen, and water, our sunbeams come back again in the flame and heat.