330 SCIENCE PROGRESS. 



thirty-two cases. Even if micro-organisms exist they are 

 incapable of infecting the egg. In twenty-two (rabbits) 

 and twenty-one cases (guinea-pigs) where the male repro- 

 ductive gland was the seat of an acute tubercular process, 

 the offspring were never infected. 2. Neither does the 

 male infect the female by way of the sperm. 3. Infection 

 takes place frequently from the female to the foetus, and in 

 an overwhelming majority of cases by way of the placenta. 



A few considerations may make the importance of Gart- 

 ner's work more evident. If bacilli exist, as they occasionally 

 do, in the product of the male gland it is probable that this 

 material, like other parts of the body, contains bacteria only 

 a few days before death, for we know that quite an abnormal 

 number of micro-organisms may invade the whole organism 

 during the last days of life. Tubercle bacilli are immotile 

 and therefore will not easily reach the oviduct or egg, a 

 matter of some importance, since it has been shown that in 

 most cases the ovum is fertilised either high up in the 

 oviduct or even at the time of liberation from the Graafian 

 follicle. Stroganoff (12) has also pointed out that the 

 uterine area is sterile, and the secretion of this is bacteri- 

 cidal, in which it resembles sputum (13) or the mucus of the 

 nasal tract which is almost free from germs (14). Lastly, it is 

 well known that a single male morphological unit is sufficient 

 for fertilisation, and if we assume with Gartner that 100 

 virulent tubercle bacilli are mixed with sperm-cells, the 

 ratio of bacteria to these would be about 1 : 22,500,000 ; it 

 is hardly conceivable on the doctrine of probabilities that a 

 bacillus would gain access to the egg. It may therefore be 

 considered, both on experimental and theoretical grounds, 

 that a germinative infection of the ovum never occurs by 

 the conveyance of micro-organisms in the male reproductive 

 cells. 



The difficulties which exist in proving that the in- 

 heritance of a specific disease may occur through an in- 

 fection of the ovum are fortunately not so great in those cases 

 where the passage of micro-organisms takes place solely 

 from the female to the fcetus by way of the placenta. It is 

 established that specific micro-organisms can pass by this 



