60 INFECTION AND IMMUNITY. 



if some of the bacilli were actually within the 

 sperm cells and capable of introduction into the 

 ovum through them, the great preponderance of 

 the spermatozoa over the bacilli renders infection 

 of the ovum improbable. In one such case Gartner 

 estimated the numerical relation of the bacilli to 

 the spermatozoa as one to 22.7 million, hence the 

 impregnating cell would very likely be an unin- 

 fected one. 



It has sometimes been assumed that leprosy may 

 be transmitted in this way, but there is no strong 

 evidence in support of it. 

 piacentai Infection of the embryo, from the mother, by 

 w& ^ Q ^ p} acen t a ^ ] ias ^ een demonstrated experi- 

 mentally, and encountered clinically, unmistakably. 

 Opinions differ as to whether actual involvement 

 i. e., infection or defects of the placenta is 

 prerequisite to the passage of micro-organisms 

 from the mother to the embryo. 



M. Wolff, on the basis of experimental work with 

 the anthrax bacillus, concluded that the uninjured 

 placenta, is an effective barrier against such a 

 transfer. It was supposed, however, that injuries 

 of the- placenta which resulted in bleeding, thus 

 establishing a temporary connection between the 

 circulations of the mother and fetus, as well as 

 other lesions metastatic in character, could well 

 result in infection of the embryo. Many others 

 also, on the basis of experimental work and the 

 study of human material, concluded that there 

 must be recognizable lesions of the placenta to 

 permit transfer from mother to child. The bacil- 

 lus of chicken cholera, a member of the hemor- 

 rhagic septicemia group of organisms, causes hem- 

 orrhages in the placenta in animals and is trans- 



