ITS CHEMICAL COMPOSITION. 45 



the morphological constituents of the cartilage, are questions still 

 to be answered. 



Fat has been found in the cartilages to the amount of from 2-g- 

 to 5g of the dry substance ; it occurs principally in the cells, but 

 is also found in solitary globules and in the intercellular substance 

 of true cartilage. Small fat-globules may be discovered in almost 

 all cartilage-cells in addition to the simple or multiple nucleus, and 

 occasionally the nucleus is rendered perfectly invisible by being 

 completely enveloped in fat. No very essential difference has 

 been found to exist between this fat and the fat of other organs. 



The amount of water present in the cartilage, and which must 

 obviously exert considerable influence on its physical properties, 

 varies in different cartilages, fluctuating between 54-g- and 70g. No 

 definite series of experiments, conducted on a given system, 

 have been made in relation to the quantity of water contained in 

 different cartilages, or as regards the specific gravity of these 

 tissues. 



From 3-g- to 6-g- of mineral substances have been found in the 

 cartilages, but the experiment was limited to the cartilages of the 

 ribs, and even these have not been examined with sufficient accuracy. 

 Phosphates of lime and of magnesia, chloride of sodium, carbonate 

 of soda, and (what is more remarkable) a large quantity of sulphates, 

 were found; but it can hardly be doubted that the latter are in part 

 due to the sulphur of the organic substance of the cartilage. The 

 occurrence of alkaline carbonates indicates, as Berzelius* has shown, 

 that the cartilaginous substance must be partly combined chemi- 

 cally with lime or soda; but whilst Fromherz and Gugert found 

 upwards of 18-g- of carbonate of lime in the ash of cartilage, von 

 Bibraf found at most only traces of alkaline carbonates in the costal 

 cartilages of the human subject at different ages, as well as in 

 those of animals. The very variable quantity of chloride of sodium 

 found in the ash of cartilage (from 1-g- to 8-g-) would seem to 

 indicate that it does not exist in chemical combination in the 

 cartilage, but that it originates in the special juice which permeates 

 that tissue, and which, unfortunately, has not yet been investigated. 



The methods to be adopted in the analysis of cartilaginous 

 tissue are sufficiently obvious from the remarks in the preceding 

 pages. 



[Much information on bone, the teeth, and cartilage, will be 



* Lehrb. d. Chem. Bd. 9, S. 563. 

 t Op. cit., pp. 412-417. 



