280 PROTECTIVE INOCULATIONS. 
chimiques). These experiments were commenced in 1881. The 
authors named say : 
‘‘In repeating the experiments of Toussaint upon-anthrax blood which 
had been heated, we made several observations which convinced us that it is 
possible to confer immunity against anthrax upon sheep by injecting under 
their skin anthrax blood which does not contain any living bacilli.” 
While immunity was produced in this way, Roux and Chamber- 
land remark that the sheep which had received a comparatively large 
dose were quite sick when subsequently inoculated with a virulent 
culture, and the immunity acquired was less reliable than that ob- 
‘tained by Pasteur’s method with two vaccines of different degrees of 
attenuation. 
In an investigation made by Hankin, in the laboratory of Professor 
Koch at the Hygienic Institute of Berlin, the results of which are given 
in a preliminary account published in the British Medical Journal 
(October 12th, 1889), the important fact was ascertained that immunity 
may be produced in susceptible animals by inoculating them with an 
“albumose” isolated from anthrax cultures. Hankin gives the fol- 
lowing account of his method of obtaining this immunizing proteid 
from anthrax cultures: 
‘In the course of my process of preparation it is precipitated from its so- 
lution by the addition of a large bulk of absolute alcohol, and well washed 
in this liquid to free it from ptomaines; it is well known that all such sub- 
stances are soluble in alcohol. It is then filtered off and dried ; then it is re- 
dissolved and filtered through a Chamberland filter. A rough estimate of 
the percentage of albumose present in the clear solution thus obtained is 
made colorimetrically by means of the biuret reaction and a peptone solution 
of known strength.” 
“‘In one experiment four rabbits (Nos. 23 to 26) were inoculated subcuta- 
neously with virulent anthrax spores. No. 26 served as a control and died 
in about forty hours. The other three rabbits had the albumose solution in- 
jected into the ear-vein at the same time. Nos. 24 and 25 each had about 
the five-millionth of their body-weight, while No. 23 had only the ten-mil- 
lionth of its body-weight of albumose. No. 25 died in less than forty-eight 
hours, but Nos. 23 and 24 survived. Ten days later Professor Koch kindly 
reinoculated these two rabbits for me with very virulent anthrax from an 
agar-agar culture. Their temperature has remained normal since then, and 
they are now alive and well afortnight after this operation. I have also suc- 
ceeded in producing immunity in mice against attenuated anthrax.” 
In a paper published in the Proceedings of the Royal Society in 
1890, Dr. Sidney Martin has given an account of his researches relat- 
“ing to “The Chemical Products of the Growth of Bacillus Anthracis, 
and their Physiological Action.” In his experiments che cultures 
were maintained for from ten to fifteen days, and the bacilli were then 
‘ removed by filtering through a Chamberland filter. The filtrate was 
found to contain: 
