46 Arrangement and Formation of the Series. [CHAP. n. 



which are subject to a considerable number of local or oc 

 casional disturbing causes. Amongst Frenchmen were in 

 cluded, presumably, Bretons, Provencals, Alsatians, and so on, 

 thus commingling distinctions which, though less than those 

 between French and English, regarded as wholes, are very 

 far from being insignificant. And to these differences of 

 race must be added other disturbances, also highly impor- | 

 tant, dependent upon varying climate, food and occupation. ! 

 It is plain, therefore, that whatever objections exist against 

 confusing together French and English statistics, exist also, 

 though of course in a less degree, against confusing together 

 those of the various provincial and other components which 

 make up the French people. 



17. Out of the great variety of important causes 

 which influence the height of men, it is probable that those 

 which most nearly fulfil the main conditions required by the 

 Law of Error are those about which we know the least. 

 Upon the effects of food and employment, observation has 

 something to say, but upon the purely physiological causes 

 by which the height of the parents influences the height of 

 the offspring, we have probably nothing which deserves to 

 be called knowledge. Perhaps the best supposition we can 

 make is one which, in accordance with the saying that like 

 breeds like , would assume that the purely physiological 

 causes represent the constant element ; that is, given a homo 

 geneous race of people to begin with, who freely inter 

 marry, and are subject to like circumstances of climate, food, 

 and occupation, the standard would remain on the whole 

 constant 1 . 



In such a case the man who possessed the mean height, 

 mean weight, mean strength, and so on, might then be 



1 This statement will receive some explanation and correction in the next 

 chapter. 



