e 
M. PASTEUR’S RESEARCHES. 97 
VM PAS TEUR’S RESEARECEDES: 
M PASTEUR, in his own name and that of his assistants, MM. 
» Chamberlan and Roux, made a communication recently to 
the French Academies of Sciences and Medicine on the results of 
his experimental inoculations with the virus of rabies. He finds 
that the virus may remain in the nervous tissues without manifes- 
tation for three weeks, even during the summer months. Virulence 
is manifested not merely in the nervous tissues, but in the parotid 
and sub-lingual glands. The granulations observed in the fourth 
ventricle, when in a state of virulence, are finer than the granula- 
tions in the fourth ventricle when in a healthy state, and they can 
be coloured by means of aniline derivatives. The virus of rabies 
injected into the veins or beneath the skin produces paralytic 
rabies, while inoculations into the spinal cord or the brain produce 
the paroxysmal form. JInoculations with quantities of the virus 
too small to be effective, have no preservative influence against 
subsequent inoculations. Whether the virus is propagated by 
means of the nervous tissues, or by absorption through the surfaces 
of the wound has not been ascertained. Finally, the experiments 
have shown that the protective “attenuation” of the virus is 
possible. ‘The energy or the nature of the virus varies in each 
species of animals. By passing the virus through different 
animals ‘‘ cultures” are obtained whose precise effects can be pre- 
dicted. Thus a “culture” has been obtained which certainly 
kills the rabbit in five or six days, and another which certainly 
kills the guinea-pig in the same time. Other things being equa 
the virulence varies inversely with the duration of the incubation. 
M. Pasteur and his assistants have good reason to believe that by 
means of a special culture they have succeeded in making twenty 
dogs absolutely proof against rabid inoculations. M. Pasteur, with 
his usual caution, asks for a little longer time before finally pro- 
nouncing on the condition of the dogs in question. ‘To devise a 
means of making the dog proof against rabies is of course to devise 
a means of almost certainly preserving man (including children) 
from this frightful disorder ; for it is almost invariably communicated 
to man and other animals by the bites of rabid dogs. 
