286 NOTES AND MEMORANDA. 



attainable. ^^'hilst 1 am firmly convinced that the same 

 holds good with regard to the synovial membrane, it must be 

 remembered that, so long as neither the treatment vs^ith 

 chloride of gold nor combined methods had been employed 

 in the investigation of this tissue, a gap was left in the 

 evidence as to the nature of the silver outlines. I anticipated 

 that these methods would render service, more especially in 

 bringing to light the exact meaning of the large white 

 stellate fields, apparently belonging to the same category as 

 those demonstrable in the cornea, but as to which it was un- 

 certain whether they belonged to groups of cells or only to 

 single ones. My investigations with respect to this point 

 have been principally made on the joints of full-grown sheep 

 and oxen, the tarso-metatarsal joints of which, and especially 

 of the last-named, yield marginal zones a finger's breadth 

 wide. The sections were always made subsequently to the 

 occurrence of the silver precipitation ; in this way the clearest 

 images are obtained, and there is no fear of cutting sections 

 of cartilage from which the marginal zone has been acci- 

 dentally rubbed off. 



" I had so often attempted, without any great measure of 

 success, to combine the staining by other reagents, such as 

 carmine and aniline, with that obtained by the silver method, 

 that I was extremely pleased to find that hsematoxylin, which 

 I made trial of at Professor Burdon Sanderson's suggestion, 

 furnished a perfectly reliable means of staining the cell- 

 nuclei. By the employment of sections which are sufficiently 

 thin to obviate any sources of fallacy arising from the pre- 

 sence of the nuclei of the more deeply seated cartilage cells, 

 it is not difficult to convince oneself that the white fields on 

 the brown ground of the silver preparation from the more 

 circular spaces of the cartilage to the stellate and epithelioid 

 forms of the inner layer of the capsule, each contain either 

 one or several (violet-coloured) nuclei. By this method, 

 then, it is demonstrable that in each of the white fields of 

 the silver preparation there lie, according to the size of the 

 fields, one or several cellular elements. It is, however, im- 

 possible by this means to say whether the cells entirely fill 

 the cavities, and by means of their processes extend into the 

 lymphatic canaliculi, forming a complete anastomosing net- 

 work or not. For the elucidation of these points the 

 treatment with gold is necessary. Thus, in two kinds of 

 preparations, one treated by the combined silver and haema- 

 toxylin method, the other with gold, appearances are met 

 with which in general form and the mode of branching of the 

 processes are more or less similar. 



