The Genotypes of Maize

THE doctrine of evolution had to overthrow the conception of permanency of specific types, generally held when Darwin's "Origin of Species" was published, because that conception was then associated with the idea of a separate original supernatural creation of each such type. It was Darwin's great triumph that lie succeeded in marshaling such an array of facts pertaining to variabilitv, as to convince the scientific world-and through the scientific world, ultimately the whole world-that everything is in a state of flux, and that there is no such thing as permanency among living things. Owing to the work of De Vries and the other early students of modern genetics, permanency of type again demands serious scientific consideration, for such permanency is no longer incompatible with the doctrine of evolution, being now associated with some form of the mutation theory. The old idea of the immutability of specific types was based -upon almost total ignorance of genetics, as was likewise the Darwinian conception of fluidity and gradual change, for although many appeals were made by Darwin to the experiences of plant and ani.ral breeders, it is now known that these experiences were the result of no such careful control of conditions or analysis of results as has been found necessary for the discovery of genetic. laws. The critical work of the past few years has wrought a great change and the new idea of permanency is gaining ground with the growth of experimental knowledge. Without granting that we have yet reached a position in which we can say definitely that types are absolutely