84 
JAMES LAW. 
presence in the system of the bacteria essential ? As the ques¬ 
tion appears to us everything serves to support the first con¬ 
clusion. * * * The facts attending the acquired immunity 
of the advanced but unborn offspring of an anthrax mother 
seem to be almost conclusive on this question. The blood of 
the dam (cow) may be swarming with bacteria, but these 
have never been found in the blood of the foetus. It is only 
reasonable to conclude that they have never entered the body 
of the foetus, or if otherwise, that they have perished very 
soon after they entered. The chemical products, on the other 
hand, being soluble in the vital fluids, presumably enter the 
foetal system along with the maternal secretions. The off¬ 
spring, when born, proves refractory to anthrax, so that there 
is the strongest presumption that it has been fortified by the 
action of the chemical products of the anthrax upon its sys¬ 
tem before birth. In this case immunity cannot well have 
resulted from any action of the growing and multiplying bac¬ 
teria on the blood or living tissues, for the evidence is all 
opposed to their presence, at any time, in the foetal system, 
much more to their growth and propagation there. Yet here, 
unquestionably, the disease in the mother has produced an 
insusceptibility in the foetus, such as would occur had it 
been itself the subject of the disease. It follows almost of 
necessity that the introduction into the system of the 
chemical products of the bacteria is equivalent in a pro¬ 
tective sense to the introduction of the bacteria themselves. 
But the mere chemical products cannot undergo increase in 
the system ; therefore we can graduate the dose of these as 
safely as we can a dose of opium or rhubarb. 
“ With this presumptive evidence we are prepared to 
study the direct results of the introduction into the system of 
the chemical products of anthrax and swine-plague, made with 
the view of securing an insusceptibility to these respective 
diseases in the future.” 
Here follows a record of Toussaint’s experiments with an¬ 
thrax, which need not be repeated. 
MY RESULTS WITH SWINE-PLAGUE. 
“ A pig was injected with one drachm of virulent swine- 
