Page:Popular Science Monthly Volume 69.djvu/227

Rh of the derivative came to bloom at the beginning of the present year, and bare mention of the existence of the derivative was given in a lecture before the Barnard Botanical Club at that time. The real value of the changes induced however lay in the transmissibility of the newly exhibited qualities. The flowers of the mutant were closely guarded and as soon as seeds were obtained these were planted to obtain a second generation. A few plants were obtained, which in every particular conformed to the new type and exhibited no return to the parental type.

Injections of the ovaries of Œenothera biennis were followed by the production of one individual, which was recognizably different from the parental type in many qualities, some of which were plainly apparent even in the earliest leaves of the seedlings. These differences have become accentuated with the adult plant and are graphically illustrated by figures 7 and 8. The succeeding generations of this mutant are yet to be tested. The parental form has been under observation for five years in cultures and in a wild condition. An aberrant form, which appears to be ever-sporting, has been previously figured, and while this form appeared in the injected or treated seeds in a normal proportion, yet the newest aberrant has not been seen elsewhere. The probability must be taken into account that it may be a mutant of rare occurrence, the cycle of which came within the experiments, but in either case it is plainly a mutant, and it only remains to be seen whether or not it was induced by the action of the zinc solution. The presumption seems to favor such an affirmative conclusion.

In finding our way about in the voluminous literature of evolution it must lie borne in mind that the subject embraces the origin and development of the universe, and that it has engaged the serious attention of workers in all branches of knowledge. The multiplicity of viewpoints has resulted in the greatest diversity of conclusions as a necessary concomitant of widely differing methods of approach to the subject. Much that has been written concerning the subject is of a purely literary or polemical character, embodying prejudices, general opinions and beliefs, putting forward conclusions drawn at long range from attempted interpretations of the results of investigations not properly considered, and brought out for the sole purpose of swaying opinion or influencing sentiment. All work of this character as well as narrow and insecurely founded investigations are futile and ineffectual except to befog the subject and hinder progress.

The problems included in a study of organic evolution are essentially physiological, and the elucidation of the mechanism and action of heredity by which qualities, characters and capacities are transmitted from generation to generation may lie accomplished only by accurate observations and experimental tests with active or living material. The examination of preserved material not in hereditary series, or the wide generalizations derived from geographic studies, may not