242 
A CONTRIBUTION. 
A CONTRIBUTION 
TO THE PATHOLOGY AND AETIOLOGY OP HUMAN AND ANIMAL 
VARIOLiE. 
Translated by F. S. BILLINGS. 
(Continued from page 201.) 
-:o:- 
From the history of retro-vaccination we deduce, that the 
lymptli of retro-vaccine is of equal value with that of true vaccina, 
and as we have, per exclusion, come to the conclusion that the 
origin of bovine variola is either to be sought in variola humana 
vera, or more generally in humanised vaccine, we will now turn 
ourselves to the proof of our conclusion. By the consideration of 
the so-called “ original, genuine” bovine variola, four things 
become apparent, aside from the sporadic character of the same: 
1. Variola vaccina is almost exclusively limited to milch cows’. 
2. Variola vaccina has its seat exclusively upon the udder of the 
same. 
3. Variola vaccina comes to observation principally in Spring 
and the early months of Summer. 
4. The development of the variola upon the udder does not take 
place concomitantly , but as a rule irregularly. 
This idiosynic character of variola vaccina offers a striking 
variation from that of all other infectious diseases. Authors have 
sought to explain it in various ways. We have already referred to 
this subject, and have found, among others, that it has been sup¬ 
posed that cattle possessed in Spring a peculiar inclination to 
cutical exanthemata, and further that changes of food, and the 
thereby functional congestion to the lacteal glands- was supposed 
to exert an unfavorable influence; and that it has been assumed 
that milk cows only possessed a disposition to this disease. By all 
who assumed the epigentic origin of the disease it remained an un¬ 
solved enigma why male, or castrated animals, calves and heifers 
were not so frequently attacked by the disease as the milk-cows, 
