Page:Popular Science Monthly Volume 82.djvu/44

40 to a mediocre line having the same average size (and other values which I can not cite here). In other words, the sum of the descendants is identical with the sum of the ascendants.

Each race differs from the others in form, stature, hardiness and chemical composition. The name population has been given to the mixtures of races, such as nature gives us in a meadow or such as we have in cultivation when segregation has not been carried far enough, that is to say, when pure lines which can be distinguished have not been separated grain by grain. This practise of selection, according to Vilmorin, has already been tested not only in the vast field of theoretical botany, but also in that of applied botany. At Svalöf, Sweden, cereals are selected according to this principle by evaluating the differences by numerical methods. All agricultural Europe follows with special attention the classic experiments of Nilson and his collaborators.

Except for the very rare phenomenon of spontaneous variation (mutation) we can by beginning with these pure lines operate in a practical way, with almost mathematical certainty, the probable error being minimal. In cereals, and especially in wheat, the characters to be studied which will be constant for a given race are: stooling, regularity of growth (that is, greater or less individual variation), average weight of the grains, resistance of the straw to lodging, length of the straw, form and length of the heads, composition of the grain (starch, sugar, nitrogen, fat, etc.), disease-resistance. In the short time at my disposal I can not explain to you the ingenious methods used to determine with precision these different characters. I wish to add only one thing. Each of these characters or their combination in pairs or groups determines the probability of success and good harvest in a given locality, and, in consequence, the more constant forms, the more pure lines there are, the more prepared will scientific agriculture be to furnish to cultivators races which will suit their soils. Now if you consider that these problems are among those that chiefly interest mankind, which demands each day its daily bread, you will understand that the slightest discovery which makes for the betterment of cereals means a noticeable increase in the wealth of a nation. If France is one of the richest countries of the world it is because her wheat production is superior, in respect to her territory, to that of all her competitors.

Now, modern agriculture, given new life by botany, has obtained in France, Germany and other civilized countries, a considerable number of these varieties, starting from cereals introduced into our country in the course of the long history of civilization; that is, from times more ancient than any documents written on parchment or carved in stone.