VARIATION IN PEDIGREE-CULTURES 223 



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 exhib- 

 ited qualities. The flowers of the mutant were closely guarded and as 

 soon as seeds were obtained these were planted to obtain a second gen- 

 eration. A few plants were obtained, which in every particular con- 

 formed to the new type and exhibited no return to the parental type. 



Injections of the ovaries of Oenothera 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 ap- 

 parent even in the earliest leaves of the seedlings. These differences 

 have become accentuated with the adult plant and are graphically illus- 

 trated bv 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 presump- 

 tion 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 atten- 

 tion 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 inef- 

 fectual except to befog the subject and hinder progress. 



The problems included in a study of organic evolution are essen- 

 tially 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 witli active or living material. 

 The examination of preserved material not in hereditary series, or the 

 wide generalizations derived from geographic studies, may not con- 



