148 MICROBES, FERMENTS, AND MOULDS. 
The following conclusions are the result of Pasteur’s 
researches into the virus of rabies. 
This virus is found in the saliva of animals and men 
affected by rabies, associated with various microbes. 
Inoculation with the saliva may produce death in three 
forms: by the salivary microbe, by the excessive 
development of pus, and finally by rabies. 
The brain, and especially the medulla oblongata, of 
men and animals which have died of rabies, is always 
virulent until putrefaction has set in. So also is 
the spinal cord. The virus is, therefore, essentially 
localized in the nervous system. 
Rabies is rapidly and certainly developed by tre- 
phining the bones of the cranium, and then inocu- 
lating the surface of the brain with the blood or saliva 
of a rabid animal. In this way there is a suppression 
of the long incubation which ensues from simple 
inoculation of the blood by a bite or intra-venous 
injection onany part of the body. It is probable that 
in this case the spinal cord is the first to be affected 
by the virus introduced into the blood; it then fastens 
on its tissues and multiplies in them. 
Asa general rule, a first attack which has not proved 
fatal is no protection against afresh attack. In 1881, 
however, a dog which had displayed the first symptoms 
of the disease of which the other animals associated 
with him had died, not only recovered, but failed to 
take rabies by trephining, when re-inoculated in 1882. 
Pasteur is now in possession of four dogs which are 
