20 ETHEL M. ELDERTON 



suggest that disease tendencies are not inherited at the same rate as physical and 

 psychological characters in cousins. 



8. General Conclusions. Our memoir has dealt with two series of cousin 

 records. The quantitative measure of the resemblance of cousins is of great importance 

 — not only on account of its bearing on eugenic marriages, but because cousins form 

 often the principal living record to assist medical diagnosis. Its determination, 

 however, presents considerable difficulties. It is not hard to collect data as to the 

 characters of cousins, when these characters can be judged without the actual presence 

 of the cousins. This was done in our first series. But when we come to the 

 quantitative measurement of cousins our experience has been unfavourable to the 

 rapid accumulation of extensive material. The passing from brethren to cousins — - 

 although the latter are a far wider group — has more than trebled the difficulty of 

 obtaining measurements. Further our choice of the hand as the organ to be dealt with 

 has possibly led to difficulty, as the treatment and use of the spanner needed more care 

 than a simple measuring tape. It was possible to explain and illustrate the use of the 

 spanner to all the male students to whom it was loaned, but in the case of women 

 helpers we had often to trust to written directions. This may be the source of the 

 high values found for the resemblance of women cousins, but we confess frankly that 

 we are not satisfied that it is so, and we must await the reduction of further material 

 before settling this point. If we turn to the 70 cases dealt with on the basis of our 

 first series, we find an average resemblance of about - 27, which tallies with the average 

 found from the eight quantitative series involving male cousins in our second 

 investigation. If this value be confirmed we should say that cousins have as much 

 significance as the parental brothers and sisters. On the other hand an examination 

 of our table shows that what may be treated as the more easily judged and reliable 

 results, show a rather higher value than '27, approximating rather to the '33 of the 

 grand parental resemblance. The pigmentation results of the second series tend to 

 confirm this view. 



We should 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. For practical 

 purposes it would hardly seem possible in the matter of marriage restrictions based 

 solely on the gametic resemblance judged by somatic characters, to differentiate 

 between the three classes. This equality of resemblance which may appear at first 

 sight paradoxical will be confirmed for uncles and aunts in a forthcoming memoir. 

 Its physiological bearing appears to us of fundamental importance as indicating that 

 a determinantal theory of heredity, emphasising alternate inheritance, must take pre- 

 cedence of any theory of simple blending for the bulk of the characters here dealt with. 



We do not consider that our data show any difference between the inheritance of 

 physical, psychical and pathological characters, which could not be accounted for by 

 (a) the difficulty of appreciating temperament, and (b) the incompleteness of the 

 cousin record. 



