spaces and, entering occasionally into the sphere of attraction of the earth, fall upon its surface, sometimes contain charcoal or a special variety of graphite; but later on, in 1887, the St. Petersburg Professors Latchinoff and Eroféeff went a step further and proved that the charcoal is occasionally transformed into diamonds; thus they extracted some diamond dust from the meteorite fallen during the previous year at Novo Urei, in the province of Penza. Some doubts were, however, entertained as regards their discovery, but the fact has been fully confirmed since by Friedel and Le Bel, who found in a meteorite from Cañon Diablo minute diamonds and carbonados exactly similar to those of Moissan.[1]
It is thus evident that the artificial reproduction of the diamond is not one of those accidental discoveries which may be made without leaving an impression upon science for many years to come. It is only one of the many advances made in a certain direction, and is the outcome of the whole drift of modern research which endeavors immensely to widen the means at our disposal for effecting physical and chemical transformations of matter. It is one step more into a new domain where chemistry, metallurgy, and mineralogy join hands together for revealing by joint efforts the secrets of the constructive forces of matter.
The study of the direct action of environment upon organisms, and of the mechanism of its action, becomes a favorite study among biologists—the "transformists" being no more a few exceptions in science, but already constituting a school which has several brilliant representatives in America, France, and Germany, as well as in this country. It is evident that almost none of the biologists engaged in this kind of research maintains any doubts as to the importance of natural selection as a factor of evolution. To use the words of one of the leading American transformists,[2] "the law of natural selection is well established, and no more under discussion." For many adaptations it offers the best and the only possible explanation. But biology would have been brought to a standstill if the idea had prevailed that, after a more or less plausible explanation of some adaptation has been given under the hypothesis of natural selection, nothing more is left to be done to explain this same adaptation. For many animals whose manners of life we hardly know at all—the study of animal life having been deplorably neglected for the last fifty years—the explanation would often be little better than a mere hypothesis; but
