368 DADD'S VETERINARY MEDICINE AND SURGERY. 
tion, and which often results in division of bony parts which 
were once immovable (the epiphysis uf the pelvis, for example) ; 
also in the seperation of cartilages from the ribs, and the shaf 
bones softened and ruined by caries (ulceration or death of bone: ' 
Big head and big jaw are terms sufficiently explicit in urdinary 
conversation ; but, in view of scientific inquiry, it is necessary t 
employ terms indicative of the pathology of the disease. We can 
not expect, however, to select any one name that shall «pply te 
all the pathological condi‘ions during the rise, progress, and ter- 
mination of this peculia: malady. The condition of the bones 
is a state of enlargement, (porousness and softening ;) hence the 
name osteo norosis. 
Causes.—We have already informed the reader that the disease 
may have an hereditary origin; otherwise, we can not account for 
its universal prevalence. In certain localities, under the ordinary 
modes of feeding and general managerient, we grant that at first 
the disease might have had an accidental or spontaneous origin, 
and finally become permanent and transmissible. For example, 
glanders and farcy afford illustrations of a spontaneous disease 
becoming contagious and transmissible. There must have been a 
me when neither of the two latter diseases existed ; hence, when 
vhe first subject became glandered, he could not have taken it by 
infection or by contagion, but it must have had a spontaneous 
origin, and, finally, became permarent. We do not pretend to 
urge that the active disease itself is transmissible; yet, in certain 
vases, a predisposition is transferred to the progeny. This may 
be called the predisposing cause; the ordinary exciting causes are 
those which disturb and derange the digestive function. The 
digestive or nutritive function is deranged, both by excessive and 
defective functional labors, or by the animal existing on food that 
does not contain the necessary amount of nitrogenous or muscle- 
making matter. This is the case when Indian corn is used as 
food for a great length of time. It is hard to digest, is deficient 
‘n nitrogen, and almost always over-distends the stomach; for, 
when submitted to the action of heat and the gastric fluids, it 
increases in bulk to ubout five or six times its original capacity. 
I have noticed that where much whole corn is fed, as in Ohio and 
Indiana, the disease is most prevalent. Associated with the pre- 
disposing causes are others—for example, hard usage, scr: abuse 
and bad stable management. 
