106 
Pasteur and his Work, 
anthrax microbe would assuredly kill. Death is more rapid in 
this disease than in anthrax, and the spleen is not involved, as 
in it. But the most valuable part of their discovery lies in the 
fact they have established — that this direct (intravenous) in- 
jection safeguards the animals so operated upon from the mortal 
effects of the disease, either naturally or artificially, which occurs 
when the virus is introduced among the muscles. The pro- 
tection has been found to last for more than two years ; as 
cattle which had received the virus at that time were inocu- 
lated with a quantity of virulent muscle-pulp, but remained 
unaffected, while another bovine, which was unprotected, died 
on receiving one-tenth part of the dose. The virus does not 
seem to be capable of attenuation by cultivation, and its intro- 
duction into the blood through a vein is the most effective, and 
hitherto the most simple, means arrived at to save cattle exposed 
to infection from death. 
This method, however, demands careful manipulation to pre- 
vent the inoculating material from escaping into the space 
between the skin and the vein, where it would set up the 
disease itself, and speedily destroy the animal. 
: It may be remembered that, a few years ago, Dr. Burdon San- 
derson undertook some experiments for the Royal Agricultural 
Society, in contagious pleuro-pneumonia of cattle, in which he 
sought to ensure protection by introducing the virus through a 
vein into the blood, instead of beneath the skin of the tail, as in 
the ordinary procedure. And as with "Black Quarter," so with 
this disease. The intravenous injection of the virus appeared to 
ensure perfect immunity against the lung disease; but there was 
great danger lest any of the virus should get beneath the skin 
during the operation, as it would give rise to so much local and 
general disturbance as in all likelihood to cause death. The 
microbes of the two diseases, while producing very little de- 
rangement to the health when imported directly into the blood 
stream, though bringing about such changes as will prevent 
attacks of their special maladies, yet find such a congenial 
habitat in the connective tissue immediately beneath the skin, 
as to multiply in appalling numbers within almost a few hours, 
and thus to destroy life. The safety of tail-inoculation for Lung 
Plague is probably to be found in the very small amount of con- 
nective tissue in that part, though the operation is no less 
•certain in its results, so far as protection is concerned. 
Pasteur has given his attention to another disease with which 
agriculturists, and pig-breeders and feeders, are only too well 
acquainted. I allude to Swine-plague, known in France as 
*' Rouget," and in (iermany as " Rothlauf." This malady has 
ifor some years assumed such a virulent and deadly character, 
