REPORT AS TO VACCINATION OF SHEEP. 
631 
numbers were entered in a book, and against each sheep a 
record was kept of the effects produced from time to time by 
the several experiments to which the animals were subjected. 
On the 24th of October, 1862, the vaccinations were com¬ 
menced, and by the 14th of November the whole of the sheep 
had been vaccinated once over, six punctures being made in 
each case. Current vaccine lymph, obtained from three 
different sources, was used: Jennerian, that in use at the 
Smallpox and Vaccination Hospital, and some which had 
been originally procured by Mr. Badcock a few years before 
from inoculating the cow with the virus of human smallpox. 
No essential difference, however, was observed in the local 
action produced by these respective lymphs, either on this 
or any subsequent vaccination of the animals. 
In the course of a few weeks we had had ample opportu¬ 
nities of satisfying ourselves of the comparative insuscepti¬ 
bility of sheep to the vaccine disease; for, on the first vaccina¬ 
tion being completed, it was found that, out of the 200, effect 
had only been produced on 71 of the animals. This fact 
determined us to procure, if possible, some primary vaccine 
lymph from the cow, and for this purpose advertisements 
were inserted in the Veterinarian. 
A small supply was obtained from three individuals, which, 
however, on trial proved to be quite inert. It is right that 
we should state we had great doubt as to whether any of this 
w r as true cowpox lymph, arising from the circumstance that 
there is a greater difficulty in obtaining genuine lymph from 
the cow than is generally supposed, and chiefly from the very 
rare occurrence of late years of the disease among these 
animals, as also from their being subject to other eruptive 
diseases which are liable to be mistaken for the true cowpox. 
For the purpose also of endeavouring to obtain primary 
lymph, recourse was had to the inoculation of cows with the 
virus of human smallpox; a proceeding that has been occa¬ 
sionally resorted to with success. Seventy-two animals were 
inoculated between the beginning of November and the end 
of August of the following year, fifty of which were tried 
two or three times in succession. We were enabled, how¬ 
ever, to charge only a few points from the whole of these 
inoculations, and the material thus obtained, when used on 
sheep, was found to have no greater effect than that produced 
by current vaccine lymph. 
We next resorted to the vaccination of some calves, with 
the view of obtaining, if possible, a supply of lymph on the 
so-called principle of retro-vaccination, namely, the passing 
of current vaccine lymph through a bovine animal. A scanty 
