HUMAN AND ANIMAL VARIOLAS. 
1S9 
settle it: at least as far as the variolic of animals are concerned, as 
will be seen on referring to my work on “ Veterinary Sanitary 
Science and Police” (vol. ii., p. 28 ); and I will now venture to 
dispute every one of the arguments brought forward to prove that 
human variola and cow-pox are due to the same virus, or are the 
same disease; or that there are only small-pox and sheep-pox as dis 
tinct variolae. With regard to animals, I may at once state that 
I believe every species has its own independent and particular 
kind of variola, and I am unable to understand why man and 
the sheep should alone have the unhappy privilege of being the 
special subjects of different forms, and this privilege be denied 
to all the other creatures. 
Whether these forms may have been originally derived from 
a common or primitive source or type, I will not now stop to in¬ 
quire ; but that they exist and compose a group of diseases rather 
than one malady, cannot be matter for doubt. That they more 
or less widely differ from each other, that in each species each 
form has a special character, and though that which is particular 
to one species may be transmitted to another species, yet the 
variola of this species need be scarcely a subject for dispute; 
while the fact that their differences are marked, not only with re¬ 
gard to their particular features, but also as to their capability of 
transference to other species, and their antagonism to each other, 
has been clearly demonstrated. Admitting that which I shall 
presently attempt to prove, that the cow has its own variola, we 
know that when this is communicated to man it does not produce 
small-pox, though it protects from it. The sheep-pox has been 
inoculated on man by many experimenters—among others, by 
Marchalli, Sacco, Yoison, and Hering, but only a small localized 
group of pustules, quite unlike the eruption of ovine variola, has 
appeared at the seat of inoculation, and no protection from small¬ 
pox or vaccinia has been conferred. Neither human variola nor 
yet vaccinia will give rise to sheep-pox, neither will their inocula¬ 
tion protect the sheep from its own variola. Horse-pox is com¬ 
municable to the cow and mankind, and protects them from their 
variolse, as well as the human species from vaccinia, while 
vaccination protects the horse from its pox. As we shall 
