Manchester Memoirs, Vol. I. (1906), No. 11. 15 



These two Laws resemble each in being physiological, 

 in that they attempt to picture the way in which characters 

 are represented in the germ cell. But they differ pro- 

 foundly in the picture which they draw. The difference is 

 so obvious that it is hardly necessary to speak about it. A 

 remark on the difference between the predictions of the 

 two Laws as to the nature of the offspring of extracted 

 recessives will suffice. Suppose that two hybrid mice 

 with grey coats and black eyes were to produce an 

 (extracted) albino — which, if the Law of Contribution 

 were true, they could not do : the Mendelian prediction 

 about the offspring of a pair of such albinos is that they 

 will be all albinos : the expectation based on the Law of 

 Contribution is that a quarter of the coat of each indi- 

 vidual child will be grey — supposing the proportions for 

 individuals in which each progenitor contributes, according 

 to that Law, to be the same as that demanded for popula- 

 tions by Galton's. The Mendelian prediction is right.* In 

 fact, the Law of Contribution is so utterly invalid that every 

 case of alternative inheritance is a contradiction of it. It 

 may apply to some cases of blended inheritance. But 

 the reason that I have formulated it, and given it a 

 name, is not that it may perhaps apply to one or two 

 cases ; but because unless it is definitely enunciated 

 it will not be reckoned as having any claims to recognition ; 

 and because, the sooner it is widely recognized, the easier 

 will it be to put an end to its confusion with Galton's 

 Law. 



4 {a). Statistical Laws^ " descriptive " .• Physiological 

 Lazvs, "■ explanatory y 



The remark might be made about the Law of Contri- 

 bution that it is Galton's Law made applicable to the 



* Darbishire :04", p. 23. 



