HUMAN AND ANIMAL VARIOLAS. 
285 
Some experimenters had previously attempted to inoculate the 
horse with human small-pox, but met with only negative results. 
The Lyons Commission undertook several series of experiments 
on this animal, somewhat similar to those on bovines, and arrived 
at analogous conclusions. The horse was as susceptible of inocu¬ 
lation as the ox tribe, and the same phenomena were produced; 
but the papular eruption developed at the punctures was so evi¬ 
dent, that no doubt whatever could exist as to its presence and its 
specific character. Indeed, it was so greatly developed that inex¬ 
perienced observers might have mistaken it for horse-pox, particu¬ 
larly at the commencement. But in horse-pox, as in cow-pox, and 
even more so in the former, there is a secretion and the formation 
of a crust; but these are nearly, if not quite, absent in the inocu¬ 
lated variola. The same experiments were made in vaccinating 
after inoculation, and vice versa , as with the ox, with exactly the 
same results. The horse was also proved to be as little adapted 
to the cultivation of small-pox virus as bovines. Three children 
were inoculated from the horses, and though the phenomena ob¬ 
served are of considerable interest, yet I cannot allude to them 
in this place, but will merely remark that the patients offered 
symptoms, mild in their degree, similar to those which follow 
small-pox inoculation. The result arrived at was that, as with 
the ox, the horse returns the small-pox virus to man just as it re¬ 
ceives it. But the production of variola in the three children 
was followed by a mild attack of natural small-pox in an unvacci¬ 
nated infant in the same room; and its mother, who had been 
vaccinated as a child, was soon after affected with a true varioloid 
eruption, with fever and other signs of general derangement. 
The variolic virus obtained from the equine species was culti¬ 
vated in mankind to the fourth generation, and produced a local 
and somewhat modified general eruption. From the second gen¬ 
eration horses were inoculated, and only the typical variolic exan¬ 
them was developed—never the unmistakable horse-pox. Trans¬ 
ferred from the horse again to the ox, in order to be assured that 
the eruption engendered by the cultivation in man of the small¬ 
pox virus, transferred originally from him to the horse, was not 
that of vaccinia, another series of experiments on cattle was in- 
