158 



Prof. Karl Pearson. 



Now several noteworthy conclusions follow at once from these 

 numbers : — 



(1) Direct Inheritance. 



(a) The dam has a great prepotency in the matter of coat-colour. 

 Mr. Galton has already remarked on this."^ We here see that, quantita- 

 tively, the dam is, on the average of both sexes, thrice as highly corre- 

 lated with the offspring as the sire. While she has reached the high 

 value 0*5, he has fallen belOAv 0-2, and the theoretical value 0-3 of the 

 unmodified law of ancestral heredity is neither satisfactory for the 

 individual cases nor for their average. 



(b) Offspring take more after the dam than the sire, but J offspring 

 more than $ after the sire, and $ offspring more than J" after the 

 dam. In other words, the parent hands down its characteristics more 

 strongly to its own than to the opposite sex. 



(c) Curiously enough, the sire's parents seem to have more influence 

 than the dam's. In particular the dam's sire has, within the probable 

 error of our determinations, no influence at all. In the unchanging line 

 of descent, the dam's dam has more influence than the sire's sire, which 

 is what we should expect from (ft) ; but (a) also makes the male element 

 of much less importance than the female, and so the dam's sire insig- 

 nificant as compared with the sire's dam. The final result is thus to 

 give a slight preponderance to the sire's over the dam's parents. 



(2) Collateral Inheritance. 



(a) The degree of resemblance between puppies of the same parents 

 is not greater when they are of the same than when they are of differ- 

 ent litters. 



It is clear, however, that we have only been able to find comparatively 

 few pairs of whole siblings from different litters, and the difference 

 between 0*5084 and 0*5257 is of the order of the probable error of the 

 differences. With greater numbers, possibly a more sensible difference 

 might be found for the correlation of siblings from the same and 

 different litters. At present there seems nothing to warrant the idea 

 that puppies from the same litter have the high degree of resemblance 

 which we find between twins in the case of mankind. 



(b) A comparison of the correlations for half siblings on the dam's 

 side and on the sire's side again emphasises, if the breeding be straight- 

 forward, the great prepotency of the dam in the matter of coat-colour. 

 The fact that we have upwards of five times as many pairs of half 

 siblings on the sire's side as on the dam's side shows how large a fashion 

 there is in selecting sires. It is possible that largely used and 



* ' Eoy, Soc. Proc.,' vol. 61, p. 404. The Table II, p. 410, requires interchange 

 of headings, as already pointed out by Mr. Galton. 



