CHAPTER VI. 



DATA. 



Records of Family Faculties, or R. F. F. data. Special Data. Measures 

 at my Anthropometric Laboratory. Experiments on Sweet Peas. 



I 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 con- 

 ditions that were of a usual kind, and in which no great 

 varieties of nurture were to be found. Natural selection 

 must have had little influence on the characteristics 

 that were to be examined. These must be measurable, 

 variable, and fairly constant in the same individual. 

 The result of numerous inquiries, made of the most 

 competent persons, was that I began my experiments 

 many years ago on the seeds of sweet peas, and that 

 at the present time I am breeding moths, as will be 

 explained in a later chapter, but this book refers to 

 a human population, which, take it all in all, is the 

 easiest to work with when the data are once obtained, 



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