122 PROCEEDINGS OF THE OHIO ACADEMY OF SCIENCE 



Thus we find that attempts to modify a character by 

 selection within pure lines within a small number of gen- 

 erations have almost universally failed, and that the few 

 apparent results to the contrary must be looked upon with 

 the suspicion that the population was a mixed race and that 

 Mendelian principles applied. 



Once again we are led to propound with still greater 

 emphasis the question, "How then has evolution taken 

 place?" "In what manner have organisms acquired their 

 characters?" "Is it possible to escape the difficulties that 

 confront the investigator on every side?" 



The application of statistical methods to problems of 

 biology has provided and will continue to provide facts of 

 decided value obtainable in no other way. Nevertheless the 

 use of data "en masse" uncoordinated with experimental 

 methods cannot solve the riddle of existence so easily as 

 some, at an earlier period at least, would have had us 

 believe. There are, however, certain investigations which 

 seem fundamental to the problem under discussion and 

 which may well be approached from the statistical side. 

 These relate to the influence of factors composing 

 the environment as well as to the part played by asexual 

 and sexual reproduction, corresponding in reality to close 

 and cross breeding, upon variability and size in organisms. 



Some studies undertaken in 1890 in connection with 

 the influence of food supply on variability^ based upon 

 the comparison of groups of Chrysanthemum leucanthe- 

 mvm L., the common white daisy, as well as Perca flaves- 

 cens Mitch., the yellow perch, indicated that the difference 

 in variability as evinced by the Coefficient of Variation for 

 a group with a maximum food supply as compared with a 

 group having a minimum food supply was extremely small 

 and well within the limits allowed by the probable error. 

 From this the inference was that external stimuli played an 

 extremely unimportant part under normal conditions as a 

 cause producing variability in general. 



1 Science, p. 728, 1907. 



