OSTEO-POROSIS. 197 



on low-lying lands. There is undoubtedly an enlarged 

 condition of the vascular elements of the bone, and a 

 decrease in quantity of the salts of lime. Almost, or quite 

 every bone in the body, in all probability, is more or less 

 affected ; in many cases there is a local cause for it, as it 

 is of far more common occurrence in certain localities than 

 in others. Professor Smith says that two cases only have 

 come under his observation in Canada, and in both cases 

 the affected animals had been fed upon food grown upon low- 

 lying land, coarse, inferior hay, etc, and had been running in 

 a swampy pasture. This disease may possibly, in certain 

 conditions, be due to the attack of a parasite. The growth 

 of the canal, and cavities of the bone increases, until the 

 walls become thin and broken down ; this takes place with- 

 out a corresponding increase in the amount of earthy or 

 animal matter. 



Si/mptoms. — The symptoms of osteo-porosis are not well 

 marked at first ; but it may be noticed that the animal, 

 instead of being as bright as before, has become languid, 

 and becomes gradually reduced in condition. The muscular 

 system becomes somewhat soft, the muscles feeling flabby, 

 or softer than in health, and after a while they become more 

 or less atrophied — the muscles of the scapular and gluteal 

 regions more particularly. The bones of the jaw and face 

 are noticed to be slightly enlarging on one side, and in some 

 cases pressure on the nasal chamber takes place, irritation 

 is set up, and a nasal discharge follows ; and occasionally 

 the air-passages of the head may be encroached upon to 

 such an extent that breathing is rendered very difficult. 

 In many cases it may be noticed that, when the animal is 

 down, it can rise only with difficulty, and often when being 

 driven along may fall, and a fracture easily occur ; hence it 

 is, by the readiness of the bones to break on the slightest 

 cause, that we know the whole osseous system is affected. 



