192 NON-INFLAMMATORY DISEASES OF BONES. 



and containing a small quantity of fat. Beneath the cartilage 

 the bone was found soft, the lamellse very thin, with the inter- 

 spaces filled with a greasy white-looking substance, fat, and the 

 extremity of the bone generally non-vascular. The synovial 

 membrane was much thickened in some joints, but the quantity 

 of synovia in all was small, dark in colour, and in some cases 

 mLxed with clots of blood. The periosteum of all the bones 

 was easily stripped off, and the bones themselves were soft 

 and easily cut with the knife. Within the bones the cancelli 

 were filled with a red gelatinous substance. The ribs, the 

 vertebrce, and all the irregular and flat bones were in the same 

 condition. The shafts of the long bones were externally but 

 little different from healthy ones; but on making a longitu- 

 dinal section of them, the medullary canal and the cancellated 

 spaces near their extremities were dark red in colour, from con- 

 gestion of the vessels and extravasation of blood into the 

 areolar spaces. In other parts a peculiar fat was found, giving 

 a paleness to the colour ; and the bones were near their ends so 

 filled that the cartilage appeared to be of a palish yellow colour, 

 and was velvety and slightly greasy to the touch. 



In some cases the teeth do not escape ; the crusta petrosa 

 being evidently increased in thickness, and more spongy than 

 natural No class or breed of horses seems exempt from this 

 disease, as I have records of cases of it in carriage horses, in 

 ponies, and in thorough-bred ones, whilst Professor Varnell's 

 cases belong to the cart breed. It seldom affects horses above 

 six years old ; frequently, indeed, the animals have ranged from 

 two up to four years old ; but my later observation teaches me 

 that very old horses are not exempt from the disease. Professor 

 Varnell enters into a very lucid examination of the cause, and 

 leaves one with the impression that it is due to food or water 

 deficient in the salts of lime. Experience, however, seems to 

 prove that the absence of lime is not a constant factor so far 

 as the life-history of the animal can be traced, nor can it be 

 conclusively proved to be due to any peculiar geological 

 formation or particular locality. One of Mr. Eobinson of 

 Greenock's cases was attacked while in London, during the 

 summer season, with symptoms analogous to those of rheuma- 

 tism, and all his cases were well-cared-for animals. It has been 

 witnessed in Shetland ponies. In America the disease is called 

 Big-head, from the peculiar swollen state of the jaws; it is 

 there supposed to be due to the feeding upon maii-e, and it has 



