PREVENTION OF RABIES BY INOCULATION. 
511 
If, for example, one infect dogs with a rabid virus which has 
virulency enough to cause the disease to come to its full devel- 
ipment, and to kill the patient in the course of twelve days, we 
ihonld not be justified in expecting preventive results from the 
ubsequent inoculation of a material which could only cause 
itronger organic changes in a very little shorter period in the 
noculated individual. It is known that Pasteur has succeeded in 
iroducing an inoculative material by carrying rabid material 
from dogs originally) successively through rabbits, which eventu- 
illy does not require more than seven days to produce lyssa in 
n inoculated individual. Should we inoculate a dog with such 
naterial, after it had already been inoculated with a material that 
equired twelve days to produce rabies, we have to fear that 
uch severe disturbances will have already taken place as to ren- 
ier the resort to preventive inoculation too late. We cannot 
xpect that the inoculation (after the bite of a rabid dog) elimin- 
tes the pathological changes; we intend that it shall produce 
uch. Preventive inoculation, after the biting of an individual 
y a rabid dog, is only to be assumed as possible of success when 
be natural inoculation has a relatively protracted period of incu- 
ation, in which the action of the specific elements is of minimum 
itensity, so that the subsequent protective inoculation is enabled 
o produce more rapid and marked changes, on account of the 
reater activity (rapidity) of the specific principle in the artificial 
laterial; or, in other words, so that , through the, subsequent (to 
le bite) inoculation, produces preventive effects. 
Dogs which have been bitten by rabid dogs do not themselves 
j ecorne rabid, generally, before from three to five weeks. Dogs 
hich have been inoculated subcutaneously with the unweakened 
atural virus require even longer than those which have been 
loculated in the brain. Such cases, which have a longer period 
F incubation, correspond more to rabies in human beings; and it 
only such cases, with an extended period of incubation, that 
’ e suited to prove the question if the inoculation with infectious 
| ibies material which has been derived from rabbits is capable of 
'eventing the outbreak of the disease. 
Although the evidence is fully as much for as against M. Pas- 
