HUMAN AND ANIMAL VARIOLA. 
291 
in various ways. Bollinger, for instance, (Sammburg, Klinischer 
Vortrag , No. 116), thinks that cow-pox owes its existence some¬ 
times to humanized vaccine—the most extended and extensive of 
all the forms of variolic contagium ; he says, “ ¥e must look,” he 
writes, “ to humanized vaccine as the source from which the 
greater number of cases of bovine variola have their origin.” A 
few instances are certainly recorded in which, apparently, acci¬ 
dental infection of cows by recently vaccinated people has oc¬ 
curred. Osiander alludes to the case of a cow which was so 
infected by a boy who had been vaccinated a short time previ¬ 
ously. In the Prussian veterinary reports on contagious diseases 
among animals for 1870-71, Koch reports that the vaccination of 
the people on a farm occasioned the infection of the cows with 
cow-pox, and in the same reports for the following year an out¬ 
break of vaccinia was announced as having taken place among a 
lot of cows, consequent upon the re-vaccination of three dairy¬ 
maids. In three weeks the disease appeared, and gradually ex¬ 
tended, so that in fourteen days, of twenty-six cows, only three 
escaped. The majority of the cows had only a few pustules upon 
the teats, but others had a number upon the teats and udder. In 
the same reports for 1874—75, Damman describes an outbreak of 
vaccinia in several sheds in the Rugen Kries, while in the district 
many children had been vaccinated, and the vaccine vesicles were 
fully developed. Schneider informed Bollinger that in 1876, 
after several children in a certain locality had been vaccinated, 
four cows in two sheds in the same place became affected with 
cow-pox; two dairymaids became accidentally inoculated from 
these, and one of the women communicated the infection to her 
children, who had not been vaccinated. Reiter also told Boll¬ 
inger that in cowsheds where he vaccinated cows, several non- 
vaccinated animals showed the characteristic indications of the 
disease, which ran its course in the ordinary manner. 
Though there is no reason to believe that cow-pox is infectious 
— i. e., virus volatile —yet there is as little reason to deny that 
cows may not become affected through contact witli newly-vacci¬ 
nated persons, provided that some vaccine lymph obtains access 
through a sore. But it is evident that this chance inoculation 
