390 
ANIMAL PATHOLOGY. 
constitution of the patient. Days and weeks and months pass 
on, and it is rare that any circumstance occurs to indicate im¬ 
pending danger. 
Of the nature of the virus we are totally ignorant. It has 
never been analyzed. That would be a process difficult to ac¬ 
complish. It is not diffused through the air—it is not commu¬ 
nicated by the breath, nor by any effluvia, nor even by actual 
contact, if the skin is sound. It must be received into a wound. 
It must come into contact with some cellular or other tissue, or 
nervous fibril, and there it lies dormant for a considerable but 
uncertain period. 
It remains perfectly undecomposed. The absorbents are ac¬ 
tively at work in removing every thing around. The nutrient 
vessels are depositing fresh matter, but it continues altogether un¬ 
changed. Whatever else is useless, or would be injurious, is taken 
up. The tissue or fibril on which the virus rests is modified or 
changed ; but this extraneous and fatal substance bids defiance 
to all the powers of nature. 
We have a thousand proofs of the power of choice in the ab¬ 
sorbent vessels. The lacteals vt^ill carry to its proper destination 
the nutrient portion of the food, while that which has nothing 
about it that will contribute to the building up of the frame is 
suffered to pass by untouched. The sphacelated and decom¬ 
posed materials of an ulcerated surface will often rapidly disap¬ 
pear, while the granulations of a healthy wound receive fresh 
accessions of substance. 
The rabid virus enters not into the circulation, or it would ne¬ 
cessarily undergo some modification in its passage through the 
innumerable minute vessels or glandular bodies, that are scattered 
through the frame. It would excite some morbid action ; or if 
it were not thus employed, or in the purposes of renovation or 
nutrition, it would be speedily ejected. 
It lies for a certain period dormant, and far longer than any 
other known poison : but, at length, from its constant presence 
as a foreign body, it may have rendered the tissue or nervous 
fibril more irritable and susceptible of impression ; or it may, at 
length, have begun to attract and to assimilate to itself elements 
from the fluids that circulate around it; and thus, increasing in 
bulk, may finally, according to a law of chemistry, supply by 
quantity that which it wanted in strength of affinity*. 
* Dr. Darwin {Zoonomia, § xxii, 33) and Dr. Percivall {bond. Med. Jour. 
1789, p. 299) doubt whether the virus is ever absorbed; and Dr. Thompson 
{Med. Chir. Journ. 1825) coincides with them. He says that the lymphatic 
trlands have never been found to be affected, although the branches of the 
cutaneous nerves running from the wound have often been inflamed. The 
