30 
GEORGE C. FAVILLE. 
emphasizes the point that rachitis is a disease peculiar to 
childhood, and from his description of rachitis and osteo¬ 
malacia, leads one to think that his differentiation is based 
rather upon the age of the subject than upon the differences 
in pathological condition. 
Williams, in his “Principles of Veterinary Surgery,” 
classes osteoporosis as a non-inflammatory disease of bone. If 
he means by that a disease of bone with no symptoms of 
inflammation present, I do not think his classification will 
hold. His definition of inflammation is “ a perverted nutri¬ 
tion of a living part, the effect of irritation or injury.” Tak¬ 
ing this definition as correct and comprehensive, the classifi¬ 
cation would perhaps hold, but it is certain that we find 
present in this disease those symptoms found where there is 
inflammation. Heat, generally with redness, pain and swell¬ 
ing are always met with. It would be more nearly correct 
to consider this disease inflammatory, the effect of a perverted 
nutrition. 
The etiology of osteoporosis is a question of much dis¬ 
pute. There can be no doubt that some fault in the hygienic 
surroundings is the predisposing cause. Just what that fault 
is it is difficult to determine. We find the disease affecting 
young and aged animals. Horses and colts that are running 
on pasture with no apparent fault in the hygienic conditions, 
and again in stables supposed to have been constructed 
according to the most modern rules of sanitary science. It 
seems to me that there is often a constitutional diathesis, not 
necessarily hereditary, which predisposes to rachitic troubles. 
Many times without doubt, we must look to the unsanitary 
construction of stables for the predisposing cause, especially 
in those extensive outbreaks which appear at times in some 
portions of the country in an enzootic form. But from the 
fact that the disease appears in horses that are not stabled or 
worked, that run upon pasture or the open prairie of the 
West, particularly some portions of the Mississippi Valley, 
we cannot conclude that the unsanitary construction of 
stables is the only predisposing cause. I can do no better in 
discussing the symptomatology of this disease, than to 
