K. Peahson and A. Lke 



377 



by thc corrclation of liomogainy aml iiTtility woiild iniicli aid us in comprehending 

 the origin o( species. 



Alth()Ui;h \ve are unablo at present to account for the high coefficients of cross- 

 assortative mating in man, it is possible to give an empirical forniula, which 

 will enable us to doterniine tliese coefficients in terms of the direct assortative 

 mating eoelHcients and the organic corrclations well within the limits of the 

 probable errors of our results. Clearly the cross-assortative mating coefficients 

 ought to vanish with botli direct and organic correlations. Hence, if ji, q refer 

 to two Organs in the husband aud p',q' to the sanie pair in thc wife, we should 

 expect the cross correlation rp,y to be of the form : 



Having satisHed myself that C and C" niight be taken as practically equal, I 

 found C as the mean of the last six entries in Table II. There resulted the 

 forniulae 



?V,,= -5342(; 



' + 'V/'V?'' ] 



whence I found the following results. 



TABLE IIU/.S. 

 Calculated and Ohserved Gross Coefficients in Husband and Wife. 



.(iii) 



The differences are well within the probable errors, and the above formulae may 

 I think be safely used, if the cross coefficients are unknown. 



(vii) Direct Parental Inheritance. 



For the resemblance in like organs between offspring and parents we have für 

 our three organs twelve cases. The correlations deduced from Appendix Tables 

 XXII.— XXXIII. are given in Table IV. below. 



It is impossible to regard these results without extreme satisfaction, not only 

 as confirmation of the general reliability of the material, bot also for the weighty 

 evidence they bring for the nature of iidieritance in man. When one remembers 

 the labour of collecting the measurements, the days spent in tabling and reducing 

 it, aud the doubts which not unnaturally arose as to its value and the value of 

 the tedious labour spent an it, the sense of satisfaction feit may be considered 

 pardonable. The surprising agreement of the results — well within the probable 



