Intimate Structure of Cartilage. 157 



When first treated with the solution of magenta the entire 

 cell is coloured, but after maceration in water the nucleus 

 alone retains the dye. The colour will disappear also from 

 the nucleus upon the application of acetic acid, and will 

 reappear in it upon subsequent washing with distilled water 

 and reapplying the magenta. The latter is rather a delicate 

 operation, but when it succeeds it well repays the trouble — 

 the cell-wall remaining quite uncoloured, the nucleus 

 coloured. 



Whenever a cell exists singly I have been unable to detect 

 an outer cell wall, but this is no longer the case when the 

 cell divides and multiplies, i.e. when groups, large or small, 

 of cells exist. These cell-walls it will be as well to call cell 

 capsules. 



OF THE CELL CAPSULES. 



1. Where, as in rib-cartilage, large spaces are seen 

 occupied by many cells, it will frequently be evident that 

 between the cells and the matrix, a delicate and slightly 

 granular membrane or capsule exists. A piece of such 

 cartilage soaked in magenta is reddened in all its parts, but 

 not equally, thus the matrix is deeply coloured and opaque ; 

 septa, equally coloured, are seen lTinning inwards and 

 dividing many of the larger groups; the cells are deeply 

 coloured but translucent, whilst surrounding and apparently 

 enclosing and separating them from the matrix, the capsules 

 are faintly coloured. If caustic potash be now added, 

 the colour vanishes from the matrix, the cells become more 

 translucent and almost colourless, whilst the capsules still 

 retain the colour. 



2. Near the margin of ossification, the oval space in which 

 the cell is contained is lined by a delicate membrane 

 which may very properly be considered a capsule. Many of 

 these have been obtained separate from the matrix, and are 

 found to agree in shape and size with the vacuoles in the 

 abandoned matrix. Very many I have distinctly seen 

 double, that is having a median septum, each partition 

 containing one cell, some have presented the appearance of 

 more or less perfect division ; others have evidently been torn 

 and lost their cell or corpuscle, whilst again, close upon the 

 bony margin, the capsule becomes much more evident, at the 

 same time that the cartilage cell is smaller and the matrix 

 more granular. These latter facts fully bear out Messrs. 



