TISSUES OF THE BODY. 183 



diametor of 0*0226 mm. (4.5). Other smaller bodies of this kind (3) still 

 bear clearly the characters of large parent-cells. 



These gelatinous collections of cells exist throughout the first year 

 after birth, and then appear to fall a prey to the centrifugal growth of 

 the fibrous ring encroaching on them. 



no. 



In the chemical investigation of cartilage, the variations corresponding 

 to the different forms in which the tissue makes its appearance should be 

 taken into account. It ought to be ascertained (a) of what substances 

 the cartilage cell, with its several parts, consists ; (&), what matters enter 

 into the composition of the system of capsules and the substance cementing 

 them together ; (e), how far the youngest layers immediately surround- 

 ing the cells differ from the older ones, which form the apparently 

 structureless matrix ; (d), how far the composition of the latter changes 

 according as it remains homogeneous or becomes granular, and like- 

 wise on the appearance of elastic fibres in it. In chemical examina- 

 tion we should be able to follow up (e) the changes which the composi- 

 tion of cartilage undergoes in the physiological metamorphoses of the 

 tissue ; and, finally, the fluid saturating the latter should come within 

 the range of inquiry, and we should look in it for the products of 

 the transformations going on in the tissue. Unfortunately, however, 

 these requirements cannot be met by any means in the present state of 

 science. 



If cartilage be treated microchemically, we immediately recognise the 

 fact that it belongs to the tissues which are not very mutable. In cold 

 water it shows but little sensibility, with the exception of the bodies of 

 the cells, which rapidly shrink up ( 104). Acetic acid has the same 

 action upon the latter, but, like other weak acids, has no effect on the 

 whole. Even sulphuric acid and strong solutions of potash are resisted 

 for a remarkably long time by the cells of cartilage (Donders and Mulder}. 

 The latter may be obtained in an isolated condition by maceration in 

 hydrochloric acid ( Virchoii). With sugar and sulphuric acid the cells 

 assume a red colour, while the intermediate substance of hyaline cartil- 

 age becomes yellowish red (Schultze). The nuclei also appear difficult of 

 solution as a rule. It is otherwise, however, with the intermediate sub- 

 stance. This may be dissolved by long-continued boiling in water, after 

 from twelve to forty-eight hours, and yields chondrin : it consists, there- 

 fore, of what is known as chondrigen. The microscopic examination of 

 the dissolving tissue during this process is a matter of some interest. 

 The cells resist the solvent action in the most determined manner, and 

 are, therefore, not formed of chondrigen or any of the other glutinous 

 compounds. It is no proof to the contrary that they are subsequently 

 dissolved. Again, the laminae of the capsules immediately adjacent to 

 the cells resist the action of boiling water longer than ths rest of the 

 ground-substance. They do not, therefore, possess the same composition, 

 though they may be said to yield chondrin. 



The same difference also is manifest in the granules of chondrigenous 

 cartilage. 



The granular clouding of the ground-substance does not disappear on 

 treatment with acetic acid or ether, but does so in a warm solution of 

 potash, and on heating in dilute, hydrochloric, and sulphuric acids. 

 13 



