58 
GEORGE FLEMING. 
tlmt the affection was not cow-pox, nor yet transmitted small¬ 
pox.* 
When we consider the question of aptitude of one species to 
receive the variola of another, we again meet with marked differ¬ 
ences. Some species will readily take the variola of another 
species, and retain it unimpaired in virulence through a continu¬ 
ous series of generations, while they will remain stubbornly re¬ 
fractory to the reception of the variola of a third species; or if 
they do receive it, it is in an abortive form, and cannot be trans¬ 
mitted beyond the second or third series of animals. 
Vaccinia affords us a good illustration of this fact. In a re¬ 
markable paper written by Chauvean, and published in 1877,f on 
the vaccinogenous aptitude of the principal vacciniferous species, 
he gives the following general conclusions derived from his ex¬ 
perimental study : 
“ 1. Classical vaccination proves that the three principal vac¬ 
ciniferous species—man, ox and horse—are equally apt to trans¬ 
mit vaccinia indefinitely, and exhibit a like vaccinogenous aptitude. 
The horse, nevertheless, is distinguished by the relative frequency 
of true generalised vaccinal eruptions, which in young animals, 
may follow cutaneous inoculation. 
“ 2. When instead of inserting the vaccine virus into the mucous 
layer of the derm, it is passed into the subcutaneous connective 
tissue, the virus manifests its action by two kinds of effects com¬ 
mon to the three species: a more or less marked local affection is 
developed, and the animals acquire vaccinal immunity as abso- 
lutel} r as if they had undergone the classical vaccination. This 
double result is obtained equally well in the three species, so that 
they are allied, as it were, in the vaccinogenous aptitude. 
“ 3. These ordinary and constant effects are not the only ones 
produced by the injection of the vaccine virus into the connec- 
* At tlie end of 1878, Dr. Klein, experimenting under the supervision of Drs. 
Seaton, Burdon-Sanderson, and Mr. Ceely, had inoculated sixteen heifers aud 
fifteen milch cows with small-pox matter taken from people at different stages 
of the disease, hut with negative results. 
t Contribution & 1’Etude dc la Vacciue Origiuelle, Journal de M<$decine 
V6t<5rinaire et de Zootechuie. Lyons, 1877. 
