344 



Miss A. Lee and Prof. Karl Pearson. 



parative correlation in the case of civilised and uncivilised races, and 

 further of determining, if possible, any general law connecting rela- 

 tive sexual variation and relative sexual correlation with the degree 

 of civilisation, and so with what is probably inversely proportional 

 to the degree of civilisation, namely, the intensity of natural 

 selection. 



The following two principles seem to flow from a study of varia- 

 tion in the organs of man : — * 



(a) Civilised man is more variable than uncivilised man. 



(b) There is a greater equality of variation for the two sexes in 

 uncivilised than in civilised races. Civilised woman appears, 

 on the whole, to be slightly more variable than civilised man. 



Both these principles are in accordance with the intensity of the 

 struggle for existence — and the amount, consequently, of natural 

 selection — being greater for uncivilised than for civilised races, and, 

 further, greater for men than for women in the latter races. 



The problem of correlation is, however, of a less simple character. 

 While the action of selection can be shown theoretically to reduce 

 variation, it by no means follows that it reduces correlation. Indeed, 

 selection may increase, decrease, or reverse correlation at the very 

 same time as it is reducing variation. t We have then the following 

 problems to guide us in our treatment of actual statistics : — 



(a) Is correlation more intense among civilised than among un- 

 civilised races ? 



(b) How does the relative correlation of the sexes differ in 

 civilised and uncivilised races ? 



(c) Is there any marked prepotency of either sex in the matter of 

 correlation ? 



These are the problems which the present calculations were de- 

 signed, not to definitely solve, but to illustrate. 



2. Unfortunately, measurements on living members of uncivilised 

 races are not very numerous, nor for the purposes of correlation 

 generally very satisfactory. There are numerous measurements of 

 skulls and some of bones, but the measurements for each individual 

 race are, from the mathematical standpoint, but few in number. 

 Hence, in the case of each determination of a coefficient of variation 

 or a coefficient of correlation, the probable error will be large. It 



* See ' Variation in Man and Woman,' by K. Pearson : " The Chances of 

 Death," vol. 1, pp. 256 — 377, where some 155 cases of human variation lor both 

 sexes are dealt with. 



f The theoretical discussion of the relation of selection to correlation forms the 

 subject of a memoir nearly completed. Actually there is some evidence to show 

 higher correlation among the working classes than among the middle and upper 

 classes of a civilised community. 



