132 : BACTERIOLOGY. 
Inherited Infection and Susceptibility to or Immunity 
from Infection. The passage of bacteria from the 
mother’s blood through the placenta to the foetus has 
been demonstrated for numerous bacteria, among the 
most important of which may be mentioned the pneu- 
mococcus, streptococcus, and tubercle bacillus. The 
detection of the tubercle bacillus by Gartner and others 
under these circumstances prevents us from denying the 
possibility that tuberculosis developing in children may 
have been due to infection taking place before birth. 
The fact, however, that calves removed from tubereu- 
lous cattle and fed on milk free from tubercle bacilli do . 
not develop tuberculosis, while those left with tubercu- 
lous cattle become tuberculous, indicates that tubercu- 
losis in man also is usually, at least, due to infection 
after birth. The infection from spermatozoa is con- 
ceivably possible in tuberculosis if the testicles are 
affected; the same may be said of syphilis; but except 
for syphilis, in which the nature of the infective agent 
is unknown, we believe that such infection is, if ever 
present, extremely rare. 
Natural immunity pertains more to species than in- 
dividuals, and such immunity is handed down by the 
parents to their offspring. If the immunity of one or 
both parents has been acquired by them during their 
lifetime previous to the birth of the offspring the im- 
munity conferred is slight or none at all. This is espe- 
cially true of the male side. In the case of the female 
parent another factor comes into play after the fructi- 
fication of the ovum—viz., the absorption of products 
from the fluids of the mother, for the placenta is no 
barrier to soluble substances. Thus, sheep which have 
been immunized to anthrax have moderately immune 
