OSTEO POROSIS. 
203 
.ETIOLOGY. 
The larger breed of our work horses, such as Normans and 
Clydesdales, are most susceptible to this disease, but still more in 
proportion the Shetland pony becomes its victim; of course others 
are also affected. These classes of horses having a predisposition 
for this disease, we will give the exciting causes a consideration. 
I have given this matter a great deal of thought, and after 
studying all the hygienic influences, have not been able to discover 
the true origin of the disease. Atmospheric influences undoubtedly 
play the most important role in developing this disease, but what 
it is that contaminates the atmosphere of the infected stables I 
have not been able to determine. Stables having the best of 
ventilation and drainage, complete in all their details for the preser¬ 
vation of health and for the comfort of horses, are, nevertheless, 
visited by this disease. It is found among horses in brick, wooden 
or stone stables, built either on high or low ground. I have 
observed that it occurs most frequently in stables whose floors rest 
on joists or stilts, forming a vacant space between the ground and 
stable floor. Horses that are kept on dirt floors, or even in 
underground stables, strange to say, are less liable to become 
affected with osteo porosis or rheumatism than those quartered 
in stables on the first, second or third floor. To meet with a case 
in an underground stable is an exceedingly rare occurrence. This 
convinces me that moisture does not contribute to its development. 
Cases of osteo porosis and rheumatism are occasionally found in 
suburban stables. Country farms seldom if ever favor the pro¬ 
duction of this malady. 
Considering the prevalence of the disease in certain localities, 
we might suspect contagion, but when we consider the fact that 
horses thus affected can be transferred to non-infected quarters 
without communicating the disease to the others, is sufficient 
reason to ignore contagion. 
The different kinds of food do not have any influence upon the 
production of this disorder; the water which the horses in 
this locality drink is river water, containing a considerable quan¬ 
tity of earthy suits, but I cannot ascribe the cause to this water, 
