REMARKS ON MICRO-ORGANISMS. 
855 
sequence of its large dimensions, is entirely retained by this 
form of filter, as is proved by the fact that the filtrate no 
longer gives rise to the organism in a cultivating liquid or in 
a living animal. Nevertheless, if injected in considerable 
quantity into the circulation of a healthy sheep, it produces 
a true vaccinating influence; that is to say, secures immunity 
from splenic fever. But, what is further extremely interest¬ 
ing, in order that this change in the constitution of the 
sheep may be brought about, the lapse of a certain time is 
essential. If a vaccinated sheep be inoculated with anthrax 
within a few days of the operation, it will die of splenic fever; 
but if from twelve to fifteen days be allowed to elapse, com¬ 
plete immunity is found to have been produced. Similar 
results followed from the injection of anthrax blood treated 
by M. Toussaint’s other method, which consists of main¬ 
taining it for a considerable time at a temperature of 55° 
Cent. (131°Fahr.), w T hich has the effect of killing the bacillus; 
after w r hich half per cent, of carbolic acid is added, to prevent 
putrefaction of the liquid. The blood treated in this way 
having been proved to be free from living bacilli by negative 
results of an experiment upon a rodent, about four cubic 
centimetres are injected into the venous system of a sheep, 
with the effect of producing the same protective influence 
against splenic fever as is ensured by the filtered blood. 
These experiments are still in progress; but M. Toussaint 
informs me that he has already ascertained the existence of 
immunity against anthrax for three months and a half in both 
sheep and dogs treated in this way. 
I need hardly remark on the surpassing importance of re¬ 
searches such as these. No one can say but that, if the 
British Medical Association should meet at Cambridge again 
ten years hence, some one may be able to record the discovery 
of the appropriate vaccine for measles, scarlet fever, and other 
acute specific diseases in the human subject. But even 
should nothing more be effected than what seems to be 
already on the point of attainment, the means of securing 
poultry from death by fowl-cholera, and cattle from the 
terribly destructive splenic fever, it must be admitted that we 
have an instance ot a most valuable result from the much- 
reviled vivisection. 
I have yet one more example to give of researches in this 
domain of pathology; and this also has reference to the 
Bacillus anthracis. The investigator in this instance is Dr. 
Buchner, assistant physician in Munich. It is well known 
that the Bacillus anthracis is morphologically identical with 
an organism frequently met with in infusion of hay, which 
