1879.] Dr. G. Thin. On Hyaline Cartilage. 



259 



nature of the tumour was at once apparent. Instead of the homo- 

 geneous ground substance seen in the other preparations, a typical 

 hyaline cartilage, with a large proportion of so-called cartilage cells, 

 was brought into view. The nuclei were well stained, bat the carti- 

 lage substance proper was only very faintly coloured. In every part 

 of all the purpurine sections the cartilage structure was perfect 



(fig- 11-)- 



The purpurine solution contains one-third per cent, alum, and one- 

 fourth its bulk of methylated alcoliol ; and it is to this composition 

 2^robably more than to the staining that the preservation of the un- 

 stable cartilage substance was due. 



Portions of the tumour which had been placed in half per cent, 

 solution of osmic acid were teased out, stained in logwood and ex- 

 amined in glycerine. Indications of the cartilaginous structure could 

 be detected, but the preparations were chiefly valuable as demonstrating 

 the nature of the cells. The cell-substance was stained a darkish 

 brown colour, the nucleus was well stained by logwood, and the 

 ground substance was very feebly stained. The outlines of the cells 

 could thus be observed in situ, as well as studied in isolated cells, 

 many of the latter floating free in the fluid. 



All the cells observed were flattened, rounded, or somewhat poly- 

 gonal bodies, with round nuclei (fig. 12). Their contours did not 

 correspond exactly with those of the rounded cartilage "capsules " in 

 which they lay. 



In order to study the structure of these so-called "capsules," por- 

 tions of the purpurine preparations were broken up. Considerable 

 fragments with even surfaces were thus obtained, with rounded nuclei 

 on the surfaces. In some of these there was no trace of the capsule 

 formation. In other fragments a long piece of cartilaginous ground 

 substance gave off laterally small curved projections, the size of the 

 projection and degree of the curvature showing that they formed parts 

 of a capsule. But in no instance was an entire capsule isolated. On 

 the other hand, a curved projection could sometimes be traced round 

 one side of a capsule, encircling nearly one-half of it, aud then passing 

 onwards to form the bent wall of another capsule. I never observed 

 these projections doubling back round, the capsule (fig. 15). 



The examination of this tumour has thus shown that most delusive 

 appearances as regards the nature of cartilage cells may be sometimes 

 produced by staining and hardening agents. Carmine a,nd eosin by 

 staining an unformed substance that exists in the structure in de- 

 fined tracts, may simulate branched protoplasmic cells, and bichro- 

 mate and logwood preparations, either in sections or teased out, may 

 as closely simulate cells with fibre processes. 



These facts justify serious doubts as to the correctness of interpre- 

 tation in all cases in which histologists have described branched cells 



