THE AMERICAN NATURALIST [Vol. XLII 



ranging around .27. The results are taken from Pearson's 

 "Family Records" and there is something in the method which 

 would seem to artificially increase the apparent resemblance. 

 Different people have been asked to give their opinions about 

 cousins whom they may happen to know. Some judges would 

 naturally be more generous than others in their estimates. It is 

 easy to see that, by cynicism on the one hand, and optimism on 

 the other, many cousins would be taken in pairs out of the 

 medium groups, where they very likely belong, and where they 

 would lower the correlation coefficient, and placed in pairs either 

 above or below the mean, whore they would improperly raise the 

 coefficients. Actual bodily measurements would not be suscep- 

 tible of error from this source and these physical measurements 

 they have attempted to obtain. So far, the latter records are 

 insufficient for full publication, but as far as they go they show 

 roughly a very high value for the coefficient r. 



The authors "conclude accordingly, from the present results, 

 that for the purposes of eugenics, cousins must be classed as 

 equally important with uncles and aunts, and that they may 

 eventually turn out to be as important as grandparents." One 

 suggestion is that any scientific marriage enactments would 

 equally allow or equally forbid marriage between first cousins, 

 as between grandparents and grandchild, uncle and niece, or 

 aunt and nephew. 



One of their conclusions regarding alternate inheritance con- 

 firms my own general contention of alternate inheritance in 

 mental and moral traits, a fact on which I laid so much stress 

 in tracing the pedigree of all the royal families. They state 

 that "a determinantal theory of heredity, emphasizing alternate 

 inheritance, must take precedence of any theory of simple blend- 

 ing for the bulk of the characters here dealt with." 



The next two memoirs to which I shall make reference, 8 are 

 especially important and tim.'ly. owing to the wide-spread prev- 

 alence of the idea that tuberculosis is an infectious disease and 

 not especially hereditary. I have even seen it printed in large 

 •Drapers' Company Research Memoirs, Studies in National Deterioration. 

 Et, A First Study of the Statistics of Pulmonary Tuberculosis. By Karl 

 Pearson, F.R.S. Dulau and Co., London, 1907. Drapers' Company Re- 

 search Memoirs. Ill, A Second Study of the Statistics of Pulmonary 

 Tuberculosis: Marital Infection. By the late Ernest G. Pope. Adirondack 

 Cottage Sanitarium, Saranac Lake, N. Y. Edited and revised by Karl 

 Pearson, F.R.S., with an appendix on assortative mating from data re- 

 duced by Ethel M. Elderton. Dulau and Co., London, l%8. 



