100 
F. S. BILLINGS. 
HOW DOES MAN DEPORT HIMSELF TOWARDS THE DIFFERENT ANIMAL 
VARIOLAS. 
We observe that, an accidental or spontaneous transmission of 
variola ovina to man does not take place, that the contagium of 
the same is not capable of causing infection if inspired by man, 
while by means of accidental injury, and occasional, but very sel¬ 
dom local infection of man with ovine may take place, which may 
lie successfully re-inoculated to sheep. On the contrary, nu¬ 
merous experiences have proven that man is sueeptible to infec¬ 
tion from the contagium of variola vaccina or equina, let the inoc¬ 
ulation be accidental or intentional; they cause a local infection, 
and protect, for a certain time, the infected man from an attack of 
variola lmmana vera. The accidental transmission of variola 
vaccina to the hands and arms of milkers belong to the most fre¬ 
quent occurences in this direction. 
Most intimately related to human variola of all the animal 
forms is undoubtedly variola ovina, which we will now consider. 
When we subject both of these processes, which are in detail anal- 
agons, to a parallel comparison, we find the origin of both de¬ 
veloped in darkness. The first report of the outbreak of variola 
ovina are derived from about the same time that variola humana 
first appeared in Europe, viz: The 15th century, (according to 
Fleming (Animal Plague) v. ovina broke out in England about 
1275, and perhaps two years previously); they were probably in¬ 
troduced from the Orient, and are at present distributed over 
nearly the whole of Europe. Seldom in the southern parts of 
Europe, they are frequent in the eastern parts of the same, in 
Russia, Hungary, North Germany, France and England. Vario¬ 
la ovina presents in its phenomonology and its typical course the 
greatest correspondence with v. humana. After an incubation’s 
period of 6 to 9 days, we may perceive upon the less-worked parts 
of the body, the eruption of an exanthema in the form of red spots, 
which shortly transform to noduli bulhe, and in the course of a 
few days to pustulse. The latter becomes augmented, gradually 
desiccate, the entire process enduring three weeks or more. I 
must not forget to mention, that as Keher, Hallier, Cohn, and 
others in the lymph of v. vaccina and humana, so Klein has found 
