DOES ACQUIRED VIGOR COUNT? 267 



vigor of the germ-cells, and* the developmental 

 vigor of particular items in the inheritance. The 

 evidence brought forward in support of this view 

 is confessedly indirect. In his experience as a 

 breeder Mr. Bonhote has been puzzled by many of 

 his results. He could not interpret them in terms 

 of Mendelian, Galtonian, or any other formulae, but 

 he found them intelligible on the theory that the 

 physiological condition of the parents at the time 

 of reproduction may influence the germ-cells and 

 their development. Low vigor in the parents will 

 tend to be echoed in weakly offspring; high vigor 

 will make for racial stability. But what is required 

 is careful and skeptical criticism of all the evidence 

 that points to the conclusion that the constitutional 

 vigor, or vitality, or healthfulness of the parents at 

 the time of parentage really counts in the devel- 

 opment of the offspring. This is a momentous 

 question, not to be answered by opinions, or on 

 hearsay evidence, or even by reference to particular 

 observations, such as the often-noticed delicacy of 

 the children of a more or less invalided and worn- 

 out father. In the case of Mammals the problem is 

 complicated by the usually prolonged period of 

 intimate symbiosis between the mother and the 

 offspring, during which it would be strange indeed 

 if the development were not sometimes perturbed 

 when there are profound changes in the maternal 

 metabolism. That such perturbations are not more 

 noticeable is largely due to subtle adaptations which 

 screen the young life from harm. 



