844 
VACCINATION OF SHEEP. 
animals, but the primary lymph failed in each case. The 
six lambs were also ovinated with success, and all recovered. 
No difference in the course of the disease produced by the 
ovinations being observed between those in which the vacci¬ 
nation took effect and those in which it failed. 
Besides the preceding instances of ovination after successful 
vaccination, twenty-five sheep, which had also been success¬ 
fully vaccinated, were ovinated, and contracted the disease. 
Two of these animals died; and it is especially worthy of 
comment that both of them had shown effect twice from vac¬ 
cination, thus proving the non-protective power of even a 
double effective vaccination. 
Sixteen sheep which had been vaccinated with success 
were exposed to the sheep-pox and took it naturally; and 
out of this number no less than eleven died, thus proving 
that the severity of the disease was in no way mitigated by 
the vaccination. 
Our experience of the vaccination of sheep therefore agrees 
with that ofHurtrel D’Arboval.who gives the following details: 
“ 1523 sheep,” he says, “were subjected to the operation 
of vaccination, and of these, 1341 contracted the vaccine 
disease, and 182 were not affected. Out of the 1341 sheep, 
429 were subsequently exposed to sheep-pox, either by 
direct ovination or by being placed among infected animals, 
and 308 of them were attacked with the malady/’ Hurtrel 
D’Arboval infers that the escape of the remaining 121 sheep 
was probably to be attributed to either their non-susceptibility 
or to some defects in conducting the experiments; and he con¬ 
cludes that “vaccination cannot be substituted for ovination/’* 
There is an impression, nevertheless, on the minds of some 
persons in France, as well as in England, with which,however, 
we do not concur, that vaccination gives to sheep a short tem¬ 
porary immunity—say for a month to six weeks—from the 
infection of smallpox. The following extract relating to this 
subject, from Gasparin’s c Des Maladies contagieuses des 
Betes-a-laine/ has been kindly furnished us by Mr. Ceeley : 
“§ 151. On ne cite qu’un tres-petit nombre d’experiences 
semblables, qui donnent un lueur d’espoir pour le succes 
d’une telle operation; mais les experiences qui lui sont con- 
traires sont nombreuses et decisives. C/est ici, i’oppose de 
ce qui nous arrive pour la clavelisation; dans celle-ci, les 
experiences affirmatives sont nombreuses, et on ne cite que 
quelques experiences negatives. 
“MM. Husson et Verrier vaccinerent 233 moutons dans 
un troupeau ou venait de se manifester le ciaveau. Au bout de 
Dictionnaire de Medeciue Yeterinaires.’—Art. “ Clavelee.” 
