354 DISEASES OF THE FEET. 



the essential nature and course of the disease. In the gelatinous 

 degeneration, all the cartilages of incrustation become gradually 

 covered over by masses of new deposition, which extend wher- 

 ever there is a synovial membrane. In the recent state, this 

 deposit has a gluey or jelly-like character varying in colour 

 from pale yellow to dark brown, and is generally intersected by 

 lines of white membraneous structure. This is the more general 

 character of gelatinous disease ; but there is another condition, 

 in which the membrane assumes a sort of granular or fungoid 

 appearance on the surface. This has been described as pulpy 

 degeneration; but all the phenomena are the same as in the 

 former case, and there is no use in making a distinction between 

 the two conditions. The deposit fills up the whole joint, and 

 acts as a kind of soft cushion, protecting the ends of the bones, 

 so that at first, when the swelling is most marked, there is com- 

 paratively little pain. 



" The cartilage of incrustation is removed by absorption ; the 

 absorption is induced by the pressure of the new material on its 

 surface, or by a peculiar action which the deposited substance 

 exerts upon the cartilage. AU the textures are ultimately in- 

 volved ; not only the synovial membrane and the cartilage, but 

 also the fibrous textures and the areolar tissue. This gives rise 

 to disorganization, and the formation of abscesses and sinuses in 

 all directions." — (Spence's Lectures on Surgerij) 



My object in describing this comparison between the white 

 swelling of the human joints and the disorganization that so 

 frequently succeeds neurotomy, is to show how a similar patho- 

 logical condition may be induced by a circumstance which at 

 first seems to be so very dissimilar; — in the human being, a 

 constitutional taint ; in the horse, removal of a portion of the 

 sentient nerve. Further inquiry may discover that the disease 

 from constitutional taint is in reality due to altered innervation 

 consequent upon that taint. 



The rupture of the tendon is due to a slow degenerative pro- 

 cess, and not to a sudden snapping of its fibres, as was formerly 

 taught. 



Now and then, however, sudden rupture of the tendon takes 

 place immediately after the operation ; but this is rare in com- 

 parison with the degenerative process, which not only involves 

 the tendon, navicular bone and ligaments, but all the surround- 

 ing structures of the foot and pastern. 



