PLANT HYBRIDIZATION BEFORE MENDEL 245 



Galton effectively combats the very general view that natural 

 selection proceeds only through small steps, 



". . . for which," he says, "it is difficult to see either the need or the 

 justification, namely, that the course of evolution always proceeds by 

 steps that are severally minute, and that become effective only through 

 accumulation," {ib., p. 32.) 



"That the steps may be small and that they must be small are very dif- 

 ferent views; it is only to the latter that I object, and only that the in- 

 definite word 'small' is used in the sense of 'barely discernible,' or as 

 small compared with such large sports as are known to have been the 

 origins of new races." {ib., p. 32.) 



Galton then points out that an apparent ground for this com- 

 mon belief lies in the fact that when intergrading forms are looked 

 for, whether in the case of plants, animals, language-forms, weap- 

 ons, utensils, or any other evolutionary product: 



"A long and orderly series can usually be made out, each member of 

 which differs in an almost imperceptible degree from the adjacent speci- 

 mens [p. 32]. But," he says, "it does not at all follow, because these 

 intermediate forms have been found to exist, that they are the very 

 stages that were passed through in the course of evolution. Counter- 

 evidence exists in abundance, not only of the appearance of considerable 

 sports, but of their remarkable stability in hereditary transmission." {ib., 

 P- 32.) 



Galton's ruling conception in dealing with the question of 

 heredity was, as is well known, to proceed by the method of de- 

 duction from the law of averages, as demonstrated by popula- 

 tions. Herein we see the prevalent misconception of his day, so 

 far as the investigation of individual inheritance is concerned — 

 that of predicting the behavior of the individual upon the basis of 

 the law of probability, as demonstrated by the outcome or product 

 of generations of like populations. 



"The science of heredity," he says, "is concerned with Fraternities and 

 large Populations rather than with individuals, and must treat them as 

 units." (p. 35.) 



The greater portion of Galton's "Natural Inheritance" is de- 

 voted to the discussion of anthropometric data collected upon the 

 subject of stature, eye-color, artistic faculty, and disease. His bio- 

 metric observations were, however, originally made upon sweet 

 peas. He states : 



"l had to collect all my data for myself, as nothing existed, so far as 

 I know, that would satisfy even my primary requirement. This was to 

 obtain records of at least two successive generations of some population 

 of considerable size. They must have lived under conditions that were 



