ON THE IDENTITY OF SMALL-FOX AND COW-POX. 45 
which must follow from this discovery; but I may state them 
shortly iu the aphoristic form. 
1. “ This discovery is new ; for although many have suspected 
the identity of small-pox in man and cow-pox in the cow, and 
have in consequence performed inoculation with the matter of 
both, yet no one has previously ascertained the possibility of 
transmitting the contagion to the cow in the gaseous form, so as 
to decide the question beyond all doubt. 
2. “ The desire of physicians and governments to discover cow- 
pox in cows, in order to revive the vaccine lymph, is more than 
fulfilled by the discovery of a simple method of engendering cow- 
pox in the cow at will. 
3. u Jenner’s discovery of the protective power of vaccination, 
hitherto imperfect, is now perfected, because the hitherto unknown 
nature and origin of cow-pox are laid open. 
4. “ All previous uncertainty regarding the quality of vaccine 
matter, its degeneration, the loss of its protective property, and 
the like, must now cease, because we have obtained a clear in¬ 
sight into the nature of cow-pox, and can lay down a substantial 
theory of its operation. 
5. “ This discovery must tend to widen the boundaries of phy¬ 
siology, pathology, and therapeutics, since it shews how the sub¬ 
tile contagion of small-pox, so hostile to the nervous system of 
man, may be conveyed in the aeriform state from him to the cow, 
excite in that animal a similar disease, but in doing so be 
changed by the special constitution of this class of animals into a 
permanent contagion of a different kind. 
G. “ An instructive lesson may be drawn from this discovery 
how the poison of diseases in the gaseous form may be commu¬ 
nicated to the lower animals, and, according to the difference in 
their constitution, engender diversified products, which may be 
then used as protective means against the diseases from which 
they originated. Such, for example, may be subsequently proved 
of scarlet fever, measles, yellow fever, and plague. 
7. “ It is now clear why, in recent times, cow-pox has been 
seldom or never seen in the cow. For the cow-pox of the cow 
arises merely from infection by the variolous exhalations from 
men recently affected with small-pox, and coming in contact with 
the cow. As epidemics of small-pox have been rare during 
the last thirty years, cows could seldom be exposed to infection, 
and have therefore seldom exhibited the disease.” 
Journal des Fra/disc hen lleilkunde, Januar . 1831. 
