LAW OF VARIATION. 53 



own blood, it inoculates her system with the consti- 

 tutional qualities of the foetus, and that, as these qual- 

 ities are in part derived to the foetus from the male 

 progenitor, the peculiarities of the latter are thereby so 

 ingrafted on the system of the female as to be commu- 

 nicable by her to any offspring she may subsequently 

 have by other males. '^ 



In support of this view, Mr. McGillivray cites a case 

 in which there was presented unmistakable evidence 

 that the organization of the placenta admits the return 

 of the venous blood to the mother ; and Dr. Harvey, 

 with much force, suggests that the effect produced is 

 analagous to the known fact that constitutional syphilis- 

 has been communicated to a female who never had any 

 of the primary symptoms. Regarding the occurrence 

 of such phenomena. Dr. Harvey under a later date says : 

 " since then I have learned that many among the agri- 

 cultural body in this district are familiar to a degree 

 that is annoying to them with the facts then adduced 

 in illustration of it, finding that after breeding crosses, 

 their cows though served with bulls of their own breed 

 yield crosses still or rather mongrels ; that they were 

 already impressed with the idea of contamination of 

 blood as the cause of the phenomenon ; that the doc- 

 trine so intuitively commended itself to their minds as 

 soon as stated, that they fancied they were told nothing 



