236 PHYSIOLOGICAL CHEMISTRY. 



chondromucoid gradually separates, while the chondroitic acid and 

 the rest of the chondromucoid remain in the filtrate. If the car- 

 tilage, which has been lixiviated, at the temperature of the body, 

 with water, is extracted with hydrochloric acid of 2-3 p. m. until 

 the collagen is converted into soluble gelatine, the remaining chon- 

 dromucoid may be removed from the insoluble residue by dilute 

 alkali and precipitated from the alkaline extract by an acid. It 

 may be purified by repeatedly redissolving in water with the aid of 

 a little alkali, precipitating by an acid and then treating with 

 alcohol and ether. 



The chondroitic acid originally formed, or that formed by the 

 decomposition of chondromucoid, is obtained by lixiviating the 

 cartilage with a 5$ caustic-alkali solution. The alkali albuminate 

 formed by the decomposition of the chondromucoid can be re- 

 moved from the solution by neutralization, then the peptone 

 precipitated by tannic acid, the excess of this acid removed with 

 sugar of lead, and the lead separated from the filtrate by H ? S. 

 If further purification is necessary, the acid is precipitated with 

 alcohol, the precipitate dissolved in water, this solution dialyzed 

 and precipitated again with alcohol, this dissolving in water and 

 precipitating with alcohol being repeated a few times, and lastly the 

 acid is treated with alcohol and ether. 



The collagen of the cartilage gives, according to MORNER, a 

 gelatine which contains only 16.4$ N and which can hardly be 

 considered identical with ordinary glutin. 



On the above-mentioned cartilages of full-grown animals the 

 chondroitic acid and chondromucoid, perhaps also the collagen, 

 are found surrounding the cells as round balls or lumps. These 

 balls (MORNER'S chondrin-balls), which give a blue color with 

 methyl- violet, lie in the meshes of an albumoid structure, which is 

 colored when brought in contact with tropaeolin. 



This albumoid is a nitrogenized body which contains loosely- 

 combined sulphur. It is soluble with difficulty in acids and alka- 

 lies, and resembles keratin in many respects, but differs from it bv 

 being soluble in gastric juice. In other respects it is more similar 

 to elastin, but differs from this substance by containing sulphur. 

 This albumoid gives the color reactions of the albuminous bodies. 



The preparation of cartilage-gelatine and albumoid may be per- 

 formed according to the following method of MORJ^ER. First re- 

 move the chondromucoid and chondroitic acid by extraction with 

 dilute caustic potash (0.2-0.5$), remove the alkali from the re- 



