F. S. BILLINGS. 
249 
(according to Rieter 1-1600), presupposing that the wound is 
large enough to offer a sufficient surface of contact for the dilu¬ 
tion. The concentration of the vaccine and the size of the wound 
stand in opposite relation to each other. Hiller found a dilution 
in glycerine of 1-10 still active, and Chauveau received positive 
results with an aqueous dilution of 1-150. 
With regard to the activity of the vaccine contagiuni in the 
blood of vaccinated persons, Hiller received negative results, but 
much depends on the manner in which the operation is performed, 
for we find other trustworthy authorities, such as Reiter, received 
positive results from inoculation made with blood of children 
which had been vaccinated eight days previously. The blood of 
a vaccinated child is also capable of infection when used in suffi¬ 
cient quantity. Ziilzer has shown the same to be true for the 
contagiuni of human variola, Osiander and Furstenburg for that 
of ovine variola. Blood therefore offers a medium by which all 
parts of an organism become infected, whether the infection 
tal ves place naturally or from artificial interference, and we can 
therefore comprehend that the children of women who are com¬ 
plicated by variola during groviditas, may become infected dur~ 
ing their intra-uterine existence, although we know that by other 
infectious diseases—anthrax, syphilis—the contagiuni circulating 
in the blood of the mother does not pass the placental septa. 
According to the period of groviditas in which the organism of 
the mother is complicated by variola will the child become in¬ 
fected intro-uterine, by which abortus is a frequent phenomena, 
or be born affected with the disease. This intra-uterine infection 
with the contagiuni of variola has been repeatedly confirmed by 
observation both by human and ovine variola, the young either be¬ 
ing born with the disease or having upon them indications of hav¬ 
ing passed through the disease intra-uteral, and so remaining 
immune against either natural or artificial infection. 
I have paid great attention to question if any which contagio 
are in condition when embodied in an organism to pass the pla- 
centa septa. In confirmation of observations previously made by 
Brenell and Davaine, 1 found that anthrax bacteria, found an im¬ 
passable septum in grovid animals affected with the placenta of 
