Page:Popular Science Monthly Volume 82.djvu/48

44 we should have a larger number of categories of types; now, of these types there would be eight categories which would be constant. These would be $$A\ B\ C,$$ $$A\ B\ c,$$ $$A\ b\ C,$$ $$a\ B\ C,$$ $$A\ b\ c,$$ $$a\ B\ c,$$ $$a\ b\ C,$$ $$abc$$; two of these types repeat the primitive parents, the others are new. If these latter are not allowed to fertilize each other or to be ferilized by other forms, but are self-fertilized, they will be constant in their descendance, which will behave like a new stable species.

From this we see that the mosaics of gens, which constitute the hereditary capital of species and varieties, are dissociable and that the gens, in the phenomena preceding or accompanying fecundation, execute a sort of chasse-croise, the final result of which is determined by the laws of probability.

The number of types and new forms increases rapidly with the number of antagonistic characters. For 2 antagonistic gens there will be 4 types; for 3 gens, 8 types; for 4 gens, 16 types; for 5 gens, 32 types; for 6 gens, 64 types; for 7 gens, 128 types—and these types are constant from the second generation (in which they appeared) on.

Here we have infinite perspectives which appear on our new scientific horizon.

But to obtain these remarkable results with the desired mathematical certainty we must start with biological unity, with a pure line, with a single grain of wheat, the parent of a whole line similar to it.

From this we see the importance of Aaronsohn's discovery; it will allow us to do methodically in a few years all that 6,000 years of cultivation and unconscious selection have gained for us and perhaps also to combine and associate characters which escaped the intuitive observations of primitive peoples.

For example, we can associate the hardiness of the wild wheat with the vigor of growth of a cultivated wheat, the rust resistance of a wild variety with the seed quality of a cultivated variety, etc.

But wheat is not for agriculture, wheat is to make bread. This making of bread is almost as old as the cultivation of wheat, and yet the conditions of fermentation necessary to raise the dough under the influence of leaven are still insufficiently known. We know that in this sour dough, the natural leaven, there are lactic bacteria which secrete an acid and give off a gas as well as alcohol. By means of this fermentation the dough, permeated by the gas which raises it, gives a lighter, more digestible bread. We are far from knowing all of the details of the process of bread fermentation. However that may be, for ages beer yeast has been introduced into the leaven, or, as in the time of the Romans, the "must of fermenting wine." These yeasts