Page:Popular Science Monthly Volume 45.djvu/546

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because animals have not been so carefully studied with reference to it. Some practices well known to horticulturists demonstrate with a singular evidence this subordination of extreme characters to the chemical composition of living matter—as in some of the methods by which new varieties and colors are obtained.

With the aid of analysis and the balance, Prof. Armand Gautier exhibits to us these new appearances of plants in relation to the formation of new chemical compounds in them. This has been done under such conditions that it can be said of every animal or vegetable hybrid that it does not represent simply the mingling or the combination of the two forms from which it is derived, but is still more the expression of new molecular combinations giving rise to intermediate chemical combinations. We have a right now to affirm that the blood of the mule, in its intimate composition, differs as much from, the blood of the horse as from that of the ass.

It is agreed that the different varieties of the European vine are variations of the same species slowly modified under the influence of man. This almost indefinite variation has not only resulted in advancing florescence and maturity and in differences in the quantities of tannin, sugar, and coloring matter in the fruit and other parts of the plant. Each of these external changes is in some way only the expression without of certain chemical changes. There appear to be as many kinds of coloring matters of seeds as there are varieties of grapes, and so different that some of them are soluble in water and some not; some crystallize, others remain amorphous; some precipitate the salts of lead in blue, and some in green. In a general way it may be affirmed, from M. Gautier's experiments, that each variety of vine has seen arise in it a new chemical species which would not have existed in Nature any more than the form with which it is associated, if man had not intervened. Man, therefore, in creating hybrids, not only makes new forms, but also throws into Nature chemical principles that had no place there.

The possibility of working in some species of animals the remarkable changes which skill has impressed on the plants of our fields and gardens can hardly be doubted. By depriving an animal of some one of the mineral principles that enter into the composition of its tissues, we should in all probability greatly modify its external form.

A single experiment is known to us which has been made in this direction by M. Chabry at the marine laboratory of Concarneau. He selected, as the animal to be experimented upon, the larva of the common sea urchin. It was seen, a few hours after it came out from the egg, as a point moving rapidly in the sea water. Observed under the microscope, it first appeared the shape of a