OF CARTILAGE. 27 



to dryness. It did not exhibit any trace of coagulation after 

 standing twenty-four hours. After being dried, it was again 

 dissolved in boiling water, on which occasion, however, a por- 

 tion remained undissolved. It was, therefore, filtered ; the 

 fluid was copiously precipitated by alum, and the precipitate 

 was, for the most part, although not entirely, dissolved, on the 

 addition of alum in excess. Acetic acid likewise rendered the 

 fluid very turbid, and an excess of acid did not entirely remove 

 the cloudiness. It was copiously precipitated by tincture of 

 gall-nuts, and acetic acid removed this precipitate again, leaving 

 a very slight turbidness. (Acetic acid likewise completely dis- 

 solves the precipitate obtained from glue by tincture of gall- 

 nuts, therefore glue, when dissolved in acetic acid, will not be 

 precipitated by the tincture.) According to these reactions, 

 the gelatinous substance obtained appears to be chondrin, not- 

 withstanding that it w r as obtained from ossified cartilage. The 

 question, therefore, arises — does the cartilaginous substance 

 which is connected with earthy matter in the foetus really 

 yield chondrin instead of the gelatine of bone, or w r as there 

 much unossified cartilage still contained in what appeared to 

 be ossified, and was that the sole source of the chondrin ? The 

 point is, at all events, worthy of renewed investigation. It is 

 surprising that the foetal cartilages should exhibit so great a 

 resistance to the action of boiling water, and that although 

 they yield a small quantity of a gelatinous substance, they do not 

 afford any which has the property of gelatinizing. 



The formative processes of cartilage hitherto described, 

 proceed, as it appears, without the presence of vessels in the 

 structure ; such at least is the case in thin cartilages, to which 

 probably the fluid parts of the blood can penetrate from the 

 vessels of the neighbouring tissues. In the branchial rays of 

 the fish, for example, I could not find any space in which ves- 

 sels could have existed ; throughout the structure masses of 

 cartilage and cartilage-corpuscles were to be seen, but no canals 

 which could have been traversed by vessels. 



The manner in which ossification proceeds now becomes an 

 interesting object of inquiry. The investigation is best pur- 

 sued by making very fine sections with a razor, from the half- 

 ossified cartilages of the extremities, vertebrae, or coccyx, of 

 the larva of Pelobatcs fuscus. The little cartilage-cells, which 



