koch’s method with tuberculosis. 
191 
4th. April 22d I inoculated in the back hypodermically 
a rabbit, No. 4, with twenty drops of the mixture of the 
medulla of rabbit No. 2, diluted with boiled water. May 
18th the same rabbit was again inoculated with brain matter 
of the dog No. 3. This rabbit was found dead November 29th. 
5th. April 22d I added three grains of medulla of No. 2 
to six drachms water and heated for an hour to 150 9 to 170° F., 
leaving the vessel wrapped in a rug so that it remained warm 
till morning. April 23d heated the mixture till it began to 
simmer, and injected one drachm hypodermically in the back 
of rabbit No. 5. May 18th inoculated this rabbit in the back 
with brain matter of dog No. 3. February 24th, 1887, inject¬ 
ed on the left cerebral hemisphere ten drops of a mixture of 
a healthy rat’s brain and boiled water. April 15th this rab¬ 
bit was in good health, when I had to leave him for Chicago. 
In view of the claim that healthy brain matter inoculated 
on the cerebrum would kill in sixteen days by paralysis, on 
February 24th, 1887, I inoculated the brains of three addi¬ 
tional rabbits with matter from the brain of a rat just killed, 
but all remained well when I was called by the United States 
Government to go to Chicago April 15th. 
We have thus traced some landmarks of the incipiency and 
development of the doctrine of immunity by the use of the 
purely chemical products of the plague-germ. We have seen 
the principle applied in practice to anthrax by Touissaint in 
1880. We have seen it applied to swine-plague by Law al¬ 
most at the same date, and published in the Agricultural Re¬ 
port for 1880. We have seen it applied to lung-plague by 
Law in 1882, and recorded in the report of the International 
Veterinary Congress of 1883. We have seen it applied to 
swine-plague in pigeons by Salmon and Smith in 1886, and 
set forth in their paper presented to the Biological Society, 
Feb. 20th, 1886, “ On a New Method of Producing Immunity 
from Contagious Diseases.” Finally we have seen the ex¬ 
periment on rabies by Law in 1886. 
Contrary, therefore, to the impression that Salmon and 
Smith inaugurated this method, the first successful step had 
been taken six years before by Toussaint, and the indispu- 
