OF CARTILAGE. a7 
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 was obtained from ossified cartilage. The 
question, therefore, arises—does the cartilaginous substance 
which is connected with earthy matter in the fetus really 
yield chondrin instead of the gelatine of bone, or was there 
much unossified cartilage still contamed 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 fiuid 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 Pelobates fuscus. ‘The little cartilage-cells, which 
