412 
PLEUR0-PNEUM0NIA IN CATTLE. 
secretion taken from diseased animals and applied to healthy 
ones.” 
This experiment, which the Commission in France pro- 
poses to make, I have studied in all its details, and I have 
decided it. The Commission did not suspect, probably, that 
this proceeding would become, instead of a means of trans- 
mitting the disease, one of extinguishing it. 
A second reason which induced me to inoculate healthy 
animals with the disease, and which indeed suggested the 
idea of doing so, was that in medical art, as applied to 
mankind, epidemic and contagious diseases are often inocu^ 
lated, and become by the very act of inoculation mild. 
The third and the principal reason which decided me to 
make my trials of inoculation was, that since 1836, we had 
had in our stables more than 500 beasts diseased with pleuro- 
pneumonia, many recovered with or without treatment ; and 
I never observed that a beast that had recovered, had the 
disease a second time ; and 1 can say with Massie, a cele- 
brated physician, who found himself in the midst of an 
immense focus of contagion (in his memorial addressed to 
Vicq-d’Azyr, speaking of contagious typhus), that experience 
had taught him that an ox, which had recovered from the 
epizootic disease, is of an inestimable value, since he braves 
with impunity all the dangers of contagion. There may, 
perhaps, be some exceptions to this rule : but if there be, 
they must be exceedingly rare. 
For the rest, the observed fact, which I assert here, is 
admitted by almost all observers. M. Yvart, inspector- 
general of the veterinary schools in France, reports facts 
which prove that the disease never attacks the same beast 
twice. M. Lafosse, of Toulouse, says the same ; MM. 
Yerheyen and Petry, two learned Belgians, perfectly well 
acquainted with the matter in question, are of the same 
opinion. 
I shall first describe the mode of operation, then give 
the details of my series of experiments, and I shall follow 
them up with some important observations and with my 
conclusions. 
MODE OF INOCULATION. 
I take the liquid pressed from the lungs of an animal 
recently slaughtered, or of one that has died of the disease ; I 
plunge into it a kind of large lancet ; then I make two or three 
punctures at the lower extremity of the tail of the animal 
that I wish to preserve from the disease ; a single drop of the 
liquid is sufficient to make the inoculation. 
