196 NON-INFLAMMATORY DISEASES OF BONES. 



osteo-porosis has not been recorded in aged horses points ont 

 most strongly that it is a disease of gi-owth ; and the circum- 

 stance of the bones being fragile and easily broken, confirms 

 the view that the cartilaginous basis, as well as the earthy 

 constituents, is not developed ; for were the disease due to non- 

 development of earthy matter only, the bones would bend, being 

 more elastic than is natural ; but in this disease they are brittle, 

 owing to the absence of the tough animal basis in sufficient 

 quantity. 



Osteo-porosis is confounded with fatty degeneration of bone, 

 but it is quite different, both physically and chemically. In the 

 one case, the bone is pink or dark red, and hydrochloric acid 

 produces but little change; but in fatty disease the bone is 

 yellowish ; and all that is left of a piece subjected to the action 

 of the acid is a small quantity of an amorphous greasy substance. 

 In fatty degeneration the cartilage degenerates into fat ; in osteo- 

 porosis it is not developed sufficiently, the bulk of the bone 

 being composed of vascular and fibrous structures mixed with a 

 portion of spongy bone ; hence they are frail, and liable to fracture. 

 In one of Mr. Eobinson's cases both fore legs were broken before 

 the animal was destroyed. 



It would be hazardous in our present state of knowledge to 

 condescend upon the cause or causes of osteo-porosis, for it wiU 

 be gathered from the foregoing observations that animals of 

 every class, no matter how treated, are subject to it; the 

 race-horse, from supposed over-feeding and over-forcing ; cattle 

 from the want of proper food; and sheep when placed upon 

 pastures which have been improved by draining and liming. 



Continental writers recommend the curative treatment of the 

 disease. In this country everything that has been done to 

 arrest its progress, such as good food, tonics, alteratives, the 

 best of attention, ventilation, &c., have all proved futile when 

 it had once been established. We must therefore conclude with 

 IVIr. Eobertson that its prevention is to be aimed at, and 

 measures taken for that purpose in every case where animals 

 are placed rmder conditions or pastured upon land favourable to 

 its development, by making such additions to their natural 

 diet as to blend the whole food into a perfect pabulum, fit 

 for the nourishment of all the tissues of the body ; for in all 

 probability it will yet be discovered that the disease is due to 



