No. 544] 



ORIGIN OF UNIT CHARACTERS 



189 



others which are obviously reversional. That he be- 

 lieved in the adding up of minor saltations there can be 

 no question; but on the admirable ground that no evi- 

 dence had been adduced in nature of evolution by major 

 saltations, he rejected St. Hilaire's hypothesis of the 

 natural appearance of entirely new types of animals 

 and plants, or of new or profoundly modified organs; 

 there was no evidence in 1872 and there is none to-day 

 of the sudden appearance in nature of such a breed as 

 the short-legged Ancon sheep. Morgan remarks, 1 1 Dar- 

 win undoubtedly supposed thai by the continuous selec- 

 tion of minor saltations a character could be slowly 

 shifted in the direction of Selection. This also appears 

 to be the opinion of the conservative mutationists of the 

 present day. ' ' 



Aside from his chief emphasis in the selection of "in- 

 dividual differences" Darwin also undoubtedly believed 

 in the selection of heritable fluctuations of proportion 

 as illustrated in his classic rebuttal of Lamarck in re- 

 spect to the long neck of the giraffe : 



If unusual length of neck in the giraffe, as in man, is 

 a saltatory and heritable character, there is no reason 

 why this classic case also may not strengthen the opinion 



of proportion, The S transmission of which is now in dis- 

 pute, however, formed a small part of Darwin's scheme, 

 nor was fluctuating variability especially connected by 

 him with the process of evolution. 



A very critical reexamination of Darwin's works 

 leads us, therefore, to largely dissent from the influen- 

 tial opinion of De Vries 7 that there was always a doubt 



