346 SPECIAL HISTOLOGY. 



a second disappears altogether in the course of development 

 (certain cranial cartilages, vide § 101) ; the third and greatest 



but the grades of the process as regards the commencing cell or the pre-existing 



granulations are as yet but little known Some authors wrongly call the 



cavities excavated in the fundamental substance, cart U age-cells ; and to the true car- 

 tilage-cells and masses of yellowish granulations or corpuscles referred to above as 

 existing in the fcetal state alone, they give the name of contents." 



Remak (' Ueber die Entstehung des Bindegewebes und des Knorpels,' Midler's 

 ' Archiv,' 1851-2) appears to have been the first, definitely to recognise the cartilage- 

 corpuscles, as the homologues of the primordial utricles of plants, — a great step, and 

 one which appears to us to lead to most important consequences. Like Schwann, 

 however, led away by the generally assumed anatomical independence of the vege- 

 table cells, Remak interprets the structure of cartilage in the same manner, and speaks 

 of the secretion of the chondrinous wall by the primordial utricles, as " parietal-sub- 

 stance" within the primary cell-membranes. He adduces no evidence, however, that 

 the facts are other than as we have stated them to be. 



Virchow (' Die Identitat von Knochen-, Kuorpel-, und Bindegewebe-korperchen 

 so wie liber Schleimgewebe, ' Verhandlung d. Phys. Med. Gesellschaft,' 1852) is an 

 important wituess in this matter. He says, " I have anew convinced myself that the 

 so-called cartilage-corpuscles are actual cells which lie in a cavity of the basis 

 (Gnindsubstanz) or in a cell-cavity presenting a double contour, and possess a 

 membrane, granular contents, and a frequently nucleolated nucleus. In the neigh- 

 bourhood of the line of ossification, in growing cartilages, as well as in the young 

 callus-cartilage of fractures, these cells are of very large size, clear, and round; in 

 the neighbourhood of the articular extremities, excessively small, compressed, and 

 dark. Under favorable circumstances, the cells, in simple cartilage, may be isolated, 

 and their peculiar relations with regard to acetic acid, which generally renders them 

 darker and collapsed, may be exhibited. Water also causes them to collapse, and 

 they thus occasionally form peculiar, jagged corpuscles, which one might be readily 

 tempted to confound with branched cells. The larger the original cell was, so much 



the more branched does its collapsed mass appear " (p. 152.) " It might 



have been expected that in the course of ossification of the cartilage, these cells would 

 be seen to pass into the irregular, anastomosing bone-corpuscles ; but nothing of the 



kind is visible A point of difficult determination is, in general, the existence 



of actual cells in the small flat cavities of cartilage, e. g. towards the surface. Very 

 frequently it would here seem as if the membrane of the cell had coalesced with the 

 intercellular substance, and only the contents with the nucleus had remained behind. 

 But on careful investigation, especially under the prolonged operation of acetic acid, 

 frequently after maceration in hydrochloric acid, we clearly see a complete cell with 

 a nucleus and contents in the cavity" (p. 153). 



Virchow gives no figures, but the above passages furnish so accurate an account of 

 what we have ourselves seen in young and in fully formed cartilage, that we have 

 thought we could not do better than cite them. The jagged appearance of the cor- 

 puscles to which he refers, is very common, and we have been led to suspect that it 

 may arise from the same cause as the very similar appearance often exhibited by the 

 colourless corpuscles of the blood, viz. a protean throwing out of processes. In 

 lis:. 129 ./, we have represented cartilage corpuscles of the forms which he describes ; 



