STRUCTURE OF THE SYNOVIAL MEMBRANES. 559 



layers, an investing cellular layer and a serous canal layer 

 (Saftcanalchenschicht) ; in opposition to Bohm, that the 

 investing cellular layer is nucleated; and, in opposition to 

 Schweigger-Seidel, that the disposition and form of the nuclei 

 in the investing layer corresponds only exceptionally to his 

 drawings. 



The relations of the articular membranes are also remarkably 

 different to the articular ligaments, as may be demonstrated in 

 the articulation of the knee, shoulder, and hip. No ligaments 

 have upon the side turned towards the articular cavity, on 

 which we may admit the existence of a sy no vial membrane, 

 any investment of epithelial cells, but their surface exhibits the 

 same markings that are apparent upon the surface of the ten- 

 dons, where they lie free in their synovial sheath. The state- 

 ment that the cavity of the joint is coated throughout by a 

 closed membrane is thus shown to be incorrect. 



The synovial membranes are characterised by the extra- 

 ordinary richness of their serous canals. It may be de- 

 monstrated by treatment with gold or chromic acid, though 

 with difficulty, that this layer contains cells or nuclei. The 

 form of the vessels presents many types. 



Bohm first maintained that the bloodvessels are directly 

 continuous with the serous canals. In reality, however, it is 

 the spaces that surround the bloodvessels which communicate 

 with the serous canals. 



Hiiter states he has never been able to see any lymphatics, 

 and that it is only in inflammatory states, in which the tension 

 of the subsynovial lymphatics is increased, that they sometimes 

 make their appearance. Landzert, on the other hand, declares 

 that they can be distinctly brought into view by his method 

 of silvering. 



I have myself been unsuccessful in accomplishing this. In 

 one instance only, in the knee-joint of a Pig, I found distinct 

 lymph cavities running off to a point, invested by an epithe- 

 lial layer, and lined by an endothelium. Similarly shaped 

 cavities are frequently also to be found in Man; but I have 

 never been successful in finding an endothelium in them. It 

 is possible that some of these were lymphatics ; but it is certain 

 that the greater number of these clear spaces are only depres- 



