OTHER DISEASES OF DOMESTIC ANIMALS. 145 
duced by a microbe, with which Pasteur was able to 
inoculate other animals (rabbits); for this purpose 
he made use of the serous discharge from the horses’ 
nostrils. The inoculated rabbits died with all the 
symptoms and lesions characteristic of the disease. 
The attenuation of this microbe by culture is 
difficult, since at the end of a certain time the action 
of the air kills it. Pasteur has, however, found an 
expedient by which to accomplish his purpose. When 
the culture is shown to be sterile in consequence of 
the death of the microbe, he takes as the mother 
culture of a fresh series of daily cultures the one which 
was made on the day preceding the death of the first 
mother culture. In this way he has obtained an 
attenuated virus with which to inoculate rabbits, and 
the same result might undoubtedly be obtained in 
the case of horses. " 
There are many other contagious diseases which 
affect domestic animals, and which are probably due to 
microbes, such as, for instance, the infectious pneumonia 
of horned cattle. This was probably the first disease in 
which the protective effects of inoculation were tried 
according to Wilhelm's method. This method consisted 
in making an incision under the animal’s tail with a 
scalpel dipped in the purulent mucus or blood taken 
from the lung of a beast which had died of pneumonia; 
sometimes the serous discharge from the swelling under 
the tail of an inoculated animal was used for others. 
Fever and loss of appetite ensued, lasting from eight 
