336 
E. BIART. 
virus, but were of a ruild type and. tlie airiiiial soon reco\eied. 
It was then proved that the animal had become insusceptible to 
the disease, for although being reinoculated with the virus sev¬ 
eral times, and in all regions of the body, there was no more 
si°ri of reaction, and the animal did not show any of the s} mp- 
fc> 7 
toms of the disease. 
Dr. Willems first isolated the pleuro-pneumonic microbe 
and with the virus inoculated dogs, cats, horses and other ani¬ 
mals without, in a single instance, producing the least incon¬ 
venience or symptoms of the disease ; but when inoculated into 
cattle they would invariably show unmistakable signs of the 
disease. The disease, it was hereby proven, was consequently 
confined to the bovine race, not being communicable to other 
animals, nor even to man. 
From this discovery it resulted that the opinion of scientists 
generally was : that the flesh of animals slaughtered in the first 
stage of the disease is not deleterious to the public health and 
may with perfect safety be used as food. 
The virus was now discovered, but it was so violent that one 
drop of it injected under the skin would invariably cause death; 
and it appeared that such a severe poison could never become a 
beneficent vaccine. 
The discoverer resumed his work, and when, after years of 
laborious researches, he found the best method of gathering the 
vaccine, the period of the disease when it is at the same time 
the most active and the most innocuous, and the place of the 
body where you can safely inoculate, he generously gave the 
government the benefit of his experiences without asking even 
a reward. 
The Department of Agriculture now appointed a committee 
of noted veterinarians to investigate the preventive mode of 
treatment. They consequently repaired to the doctor s home, 
whose stables it was claimed were proof against the disease, he 
having inoculated all of the animals with the pleuro-pneumonic 
virus. The doctor being asked to have introduced in his 
stables and mixed with his own other cattle manifestly diseased 
