188 
GEORGE FLEMING 
the subject of human and animal variolas and their relationship. 
Strange it is to note doubt and hesitation, and unfruitful discus¬ 
sions as to the nature, advantages, and dangers of vaccination, 
when we reflect that it has been practised for ninety years, and is 
universally adopted all over the world as a prophylactic against 
one of the direst of the pestilences which haunt the human family. 
But so it is; and, as before observed, the tendency among 
medical men, at least in this country, appears to be in favor of 
small-pox and cow-pox being due to one and the same virus; in 
opposition to the Jennerian doctrine, that the cow-pox was derived 
from horse-pox, and had none but an antagonistic relationship to 
human variola. Their belief seems to be founded on the reports 
of certain experiments performed by four or five persons (Gass- 
ner, Thiele, Sonderland, Badcoek, Ceely), in which positive results 
were obtained some forty or fifty years ago, and on accounts of a 
few instances in which small-pox was said to have been commu¬ 
nicated from sick people to animals. Jenner, according to this 
opinion, was mistaken ; his cow-pox was not derived from “ greasy- 
legged” horses, but from the small-pox-stricken people who went 
about and handled the milch cows, and so infected or inoculated 
them. It follows that only cows were (and are now) affected ; that 
cow-pox was much more prevalent in those days than now, be¬ 
cause small-pox was more prevalent; that only mankind and sheep 
have a distinct variola of their own, for the simple reason that those 
who entertain this opinion never saw or heard of any other species 
being affected with variola; that failures in recent attempts to 
produce cow-pox, by inoculating cattle with small-pox virus, and 
the production of small-pox when the matter of the eruption was 
transferred from the cows to children, were due to the human 
virus being merely deposited in a little pouch in the animal’s skin, 
where it did not undergo the supposed modification; and that, 
though all recent experimenters have failed in developing cow- 
pox from small-pox, yet at the period mentioned it was accom¬ 
plished without difficulty. 
Deeply impressed with the vast “importance of arriving at the 
truth in such a grave cpiestion, I have for many years devoted 
much attention to it, and have already done what in me lay to 
