192 NON-INFLAMMATORY DISEASES OF BONES. 



and containing a small quantity of fat. Beneath the cartilage 

 the bone was found soft, the lamellae 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 

 mixed 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 

 vertebrae, 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. In no instances have I heard or 

 seen it affecting horses above six years old ; frequently, indeed, 

 the animals have ranged from two up to four years old. In my 

 experience males only have been attacked by it. Professor VarneU 

 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 ; but my experience goes to prove that food and 

 water have nothing to do with it, nor can I conclusively trace it 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 

 rheumatism, 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 maize, and it has 



