368 DADD'S VETERINARY MEDICINE AND SURGERY. 



fcion, and which often results in division of bony parts which 

 were once immovable (the epiphysis of the pelvis, for example) ; 

 also in the separation of cartilages from the ribs, and the shaft 

 bones softened and ruined by caries (ulceration or death of bone-: > 

 Big head and big jaw are terms sufficiently explicit in ordinary 

 conversation; but, in view of scientific inquiry, it is necessary to 

 employ terms indicative of the pathology of the disease. We caD 

 not expect, however, to select any one name that shall ipply to 

 all the pathological conditions during the rise, progress, and ter- 

 mination of this peculiar malady. The condition of the bones 

 is a state of enlargement, (porousness and softening ;) hence the 

 name osteo porosis. 



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 management, 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 

 ,»he 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 permanent. We do not pretend to 

 urge that the active disease itself is transmissible ; yet, in certain 

 cases, 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. 

 in 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 about 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. 



