PATHOGENESIS AND DEVELOPMENT OF DISEASE. 
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PATHOGENESIS AND DEVELOPMENT OF DISEASE. 
By W. L. Rhoads, D.V.S., Lansdowne, Pa. 
A Paper read before the Pennsylvania State Veterinary Medical Association. 
During yesterday’s meeting I heard some of our fraternal 
friends say what they thought we should do to keep up with the 
times. To do this we have determined the veterinary profes¬ 
sion shall become the foundation upon which the science of pro¬ 
tecting the public health shall depend. We can best accom¬ 
plish this object by a thorough and comprehensive study of the 
origin and development of disease—which is any departure 
from the state of health, either functional or organic. Though 
the physician attempts to regulate and control the disease after 
it has found lodgment in our systems, the veterinarian strives 
to prevent its introduction into our bodies by purifying the meat 
and milk supply of his community, as they are probably the 
most potent factors in the development and transmission of 
disease. Meat left uncovered in the open air for a few hours in 
a moderate temperature soon becomes thoroughly infested with 
bacteria, especially if moisture is present. 
Milk is a most favorable media for the nourishment and de¬ 
velopment of the germs of disease. These germs may come from 
the cow, as in the case of tuberculosis or parenchymatous mastitis, 
which has produced throughout a milkman’s route gastro-intes- 
tinal catarrh, or the germ may be added to the milk from human 
sources, as in the case of scarlet fever, diphtheria or typhoid fever. 
Every epidemic of typhoid in civilized and enlightened countries 
is now traced to or ascribed to infection from milk or water and 
milk has proven to be the better media for its transmission. As a 
considerable percentage of the milch cows in a civilized country 
are consumptive, and as germs of this dread disease are transmitted 
through the milk from such cows to human consumers, it be¬ 
comes necessary for enlightened and progressive boards of health 
to assume the sanitary supervision (through their veterinarian) of 
the milk supplies of their respective communities. I realize I 
