Page:Popular Science Monthly Volume 67.djvu/70

64 with them that which nature herself seems unable to do, namely, to dissociate them from the rest of the organization and perfect them in this way or in that. It is this meddling with the fluctuating characters of the species that has been the characteristic procedure of the Darwinians, in their attempt to show how new species have been created. In contrast to this method, the theory of the survival of species assumes that a form once made does not have its individual parts later disassociated and adjusted to better fit the external needs of the species. Such a new form can change only by becoming again a new species with a new combination of characters; some of which may be more developed in one direction than before, others less; etc.

New forms on the Darwinian theory are supposed to be created by a process of picking out of individual differences. If, in addition to this, Darwin supposed that at times varieties and species crowd each other out nothing new is thereby created. On the other hand the theory of the survival of definite variations refers the creation of new forms to another process, namely, to a sudden change in the character of the germ. The creating has already taken place before the question of the survival of the new form comes up. After the new form has appeared the question of its persistence will depend on whether it can get a foothold. The result is now the same as when species crowd each other out. This distinction appears to me to be not a matter of secondary interest, but one of fundamental importance, for it involves the whole question of the 'origin of species.' So far as a phrase may sum up the difference, it appears that new species are born; they are not made by Darwinian methods, and the theory of natural selection has