27 
than five-hundred and sixty-eight persons, and fifty thousand 
animals perished from this fell disorder. Here again M. Pasteur 
detected the special fungoid growth or bacillus, which produced 
these disastrous results, and found that by cultivating the germs 
in different media, he was able so to weaken or modify their 
virulence, that vaccination with this attenuated virus protected 
healthy animals from a severe attack of the disease, without 
seriously affecting their health. 
In a celebrated test experiment, which was watched with the 
keenest interest by scientists as well as by many practical men, M. 
Pasteur inoculated twenty-five sheep out of a flock of fifty, and 
after their recovery from the slight illness thus produced, he 
publicly inoculated the whole flock with the ordinary virus of 
anthrax. The result was precisely in accordance with his pre- 
dictions; within forty-eight hours the twenty-five uninoculated 
sheep were dead, while those which he had previously inoculated 
with the weakened virus, were alive and well. No less than one 
million seven hundred thousand sheep, and ninety thousand oxen, 
have been vaccinated with the preventative virus during the last 
few years, the result being that the mortality from this plague, 
which formerly averaged ten per cent., has been reduced to less 
than one per cent. The system of preventative inoculation is now 
universally adopted in all those districts in France where anthrax 
was formerly prevalent. 
But, perhaps, M. Pasteur’s most brilliant achievement is in 
connection with his experiments for the prevention of the awful 
disease called rabies, for, although he has not yet identified its 
special bacillus, he has found that by cultivating and weakening 
the virus of the disease, a lymph is produced, with which he be- 
lieves dogs or other asimals may be effectually protected by vacci- 
nation from rabies. He has also greatly advanced our knowledge 
of this dire disease, for whereas the poison was formerly supposed 
to exist only in the saliva of the rabid animal, M. Pasteur has 
traced it definitely to the nerve centres. An animal inoculated 
with virus from the spinal marrow of a rabid animal developes the 
disease far more rapidly than one inoculated only with the saliva. 
The fact that the nerve centres are the seat of the disease goes far, 
according to M. Pasteur, to explain the cause of his anti-rabic 
treatment not being invariably successful. The length of time 
’ occupied by the virus from the tooth of a rabid animal in reaching 
the nerve centres varies according to circumstances, and should the 
central nervous system be affected before the inoculation with the 
weakened virus takes place, the latter is of course valueless. 
The difference of opinion on the Pasteurian method of dealing with 
the rabies is very great, and the various arguments for and against 
