HUMAN AND ANIMAL VARIOLAS. 
24:3 
human variola were inoculated on the cow, it could be so modified 
as to produce true primary vaccinia, or whether variola was so 
foreign to the bovine species that its inoculation in cattle was im¬ 
possible, alludes to the ability of Chauveau, and to the results of 
his labours, which demonstrated that the truth lay on neither side; 
These results proved that human variola could be inoculated 
on the cow and horse with the same certainty as vaccinia; but 
they also showed, contrary to what takes place in the human 
subject, that the primary effects produced by inoculation with the 
two viruses were absolutely different. Thus, with the ox, the 
small-pox virus only determines a local eruption of papules, often 
so small that they would pass unperceived if one were not warned 
of their existence. Hence the mistake made by some experi¬ 
menters, who have denied that small-pox could be inoculated on 
bovines. The vaccine virus, on the other hand, engenders the 
typical pustular eruption, with its large characteristic boutons. 
Analogous differences are observed, continue the Academy 
commissioners, on animals of the equine species. These differ¬ 
ences are still more manifest in the same animal inoculated simul¬ 
taneously with the two viruses; the two eruptions are then 
developed simultaneously without appearing to influence each 
other, and preserve their special characters. But the two viruses 
are not less capable of acting one on the other, and so reciprocally 
neutralising each other—just as in man—when inoculated suc¬ 
cessively on the same animal. In fact, human small-pox gen¬ 
erally fails on vaccinated animals, while the vaccine virus as 
commonly fails on those which have been previously submitted 
to variolous inoculation. In no case had Chauveau and his 
colleagues seen the slightest tendency to rapprochement between 
the characters of the two eruptions in the horse and ox. In 
attempting to cultivate the variolic virus on these two species, 
they have even discovered that it cannot become acclimatised in 
them, and that, with the ox in particular, it becomes impotent at 
the second or third generation; while the vaccine disease is prop¬ 
agated indefinitely from one individual to another. With regard 
to inoculation of man with this variolic virus which had been 
transiently (passagerement) implanted in the organism of animals, 
