HUMAN AND ANIMAL VARIOLA?. 
433 
the cow only the centre is covered. In the ox the lymph is rarely 
abundant, and there is never anything more than a thin brown 
crust; but in the horse the crust is wide, thick, rough on the sur¬ 
face, transparent and citrine-tinted. 
Before leaving the subject of horse-pox, it may be observed 
that Spinola remarked that the low-lying regions along the Baltic 
appeared to be more infested with the disease than elsewhere. 
SHEEP-POX. 
Sheep-pox differs from cow and horse-pox in having a history 
extending over some centuries, and closely in resembling small¬ 
pox in its extension—this depending not only on its contagious 
but also on its infectious properties—and the eruption being more 
or less general over the body. Indeed, so far as intensity of viru¬ 
lence is concerned, its appearing in an epizootic form, as well as 
the serious symptoms and mortality accompanying sheep-pox, 
there is the closest resemblance between it and human variola. 
We have seen that cow-pox and horse-pox are far from being 
serious disorders, the affected animals, in the majority of instances, 
being very little, if at all, disturbed in health, while the diseases 
are not infectious, and not always very contagious.* 
* Depaul believed horse-pox to be infectious, aud cites, in support of his 
opinion, an instance in which a cow was inoculated with the lymph from the 
nostril of ahorse, when seventeen other cows, inhabiting the same shed, were 
soon after infected, cow-pox pustules appearing on the udder and teats. In ad¬ 
dition, a horse kept in a badly-constructed box in this stable, and breathing the 
same atmosphere as the cows, was also affected, the eruption showiug itself 
on different parts of its body. It is not at all improbable, however, that the 
cow-keeper and his assistants, who handled the diseased and healthy animals 
alike, were the chief agents in spreading the malady. Indeed, the wife of the 
cow-keeper, in milking the cows, was vaccinated on one of her fingers, aud yet 
coutinued to handle the teats of the others, notwithstanding the pain she exper¬ 
ienced. Bouley has bad perfectly healthy horses and cows cohabit with diseased 
horses, and when the malady was produced in them he was always able to trace 
it to direct contact. During the epizooty at Alfort, in 1863, it was possible to 
transmit the horse-pox to a series of horses by placing them one after another in 
a stall which had been occupied by a diseased horse. Each animal became af¬ 
fected in turn, and at times its immediate neighbors also ; but beyond those in 
that stable there were no further transmissions, all the other horses remaining 
unaffected. As Bouley justly remarked, a really infectious disease does not com¬ 
port itself in this manner. Veterinary Surgeons Turennne aud Mathieu have 
also experimentally demonstrated that horse-pox is not infectious, and this is in 
accord with my own experience. 
