Heredity and the Origin of Variations. 155 



reduce the level of now one and now another character. 

 But how it can raise the level beyond that attained by 

 either parent is not obvious. It is perhaps possible, though 

 Professor Weismann does not, I think, suggest it, that, by 

 a kind of compensation,* the reduction of certain characters 

 may lead to the enhancement of others. Let us revert to 

 the illustration on p. 150, where each individual has an 

 available store -of forty units of growth-force ; and let us 

 express by the minus sign the units lost in the parents by 

 the extrusion of the polar cell and an analogous process 

 which may occur in the genesis of the sperm. Then the 

 units of growth-force which may thus be lost by a " reducing 

 division " in b, c, and e may be, in the offspring, applied 

 to the further growth of a ; thus 



Parents. Offspring. 



a "lO T^T" ~10^ 14 



b 8-1 10-3 1 



c 9-1 5-1 6 



d 1 9 8 



e 6-2 6 5 



Here the reduction of the characters b, c, and e has 

 led to the enhancement of a, which thus stands at a higher 

 level than in either parent. 



On such an hypothesis we may, perhaps, explain the 

 fact to which breeders of stock testify that the organ 

 strongly developed in both parents (a) is yet more strongly 

 developed in some of their offspring, and that weakly parts 

 (e) tend to become still weaker. I know not whether this 

 way of putting the matter would commend itself to Professor 

 Weismann or his followers ; but some such additional 

 hypothesis of transference of growth-force from one set of 

 organs to another set of organs seems necessary to complete 

 his hypothesis. 



Professor Weismann's view, then, assumes (1) that the 

 cell-division which gives rise to the ova in the ovary is so 

 absolutely equal and similar that all ova have precisely 



* JThe law of compensation of growth or balancemeut was suggested at 

 nearly the same time by Goethe and Geoffroy Saint-Hilaire. The application 

 in the text has not, so far as I know, been before suggested. 



