TISSUES OF THE CONNECTIVE SUBSTANCE. 237 



muiuing cartilage by water, and then boil with water in a PAPIN'S 

 digester. The collagen passes into solution as gelatine, while the 

 albumoid remains undissolved (contaminated by the cartilage-cells). 

 The gelatine may be purified by precipitating with sodium sul- 

 phate, which must be added to saturation in the faintly-acidified 

 solution, redissolving the precipitate in water, dialyzing well, and 

 precipitating with alcohol. 



According to MORNER, no albumoid is found in young car- 

 tilage, but only the three first-mentioned constituents. Neverthe- 

 less the young cartilage contains about the same amounts of nitrogen 

 and mineral substances as the old. 



HOPPE-SEYLER found in fresh rib cartilage 676.7 p. m. water, 

 301.3 p. m. organic and 22 p. m. inorganic substance. In the 

 cartilage of the knee-joint 735.9 p. m. water, 248.7 p. m. organic 

 and 15.4 p. m. inorganic substance have been found. The ash of 

 cartilage contains considerable amounts (even 800 p. m. ) of alkali 

 sulphate, which probably did not exist originally as such, but is 

 produced in great part by the calcining of the chondroitic acid and 

 the chondromucoid. The analyses of the ash of cartilage therefore 

 cannot give a correct idea of the quantity of mineral bodies exist- 

 ing in this substance. PETERSEN and SOXHLET have found 940 

 p. m. NaCl in the ash from the cartilage of a shark, and such 

 cartilage can scarcely contain quantities of chondromucoid or chon- 

 droitic acid worth mentioning. The cartilage of the ray (Raja 

 batis LIN".), which has been investigated by LONNBERG, contains 

 no albumoid and only a little chondromucoid, but a large propor- 

 tion of chondroitic acid and collagen. 



The Cornea. The corneal tissue, which is considered by many 

 investigators to be related to cartilage in a chemical sense, contains 

 traces of albumin and a collagen as chief constituent, which C. TH. 

 MORNER claims contains 16.94$ N. According to him it contains, 

 a mucoid which has the composition C 50.16, H 6.98, N 12.8, and 

 S 2.05 per cent. On boiling with dilute acid this mucoid yields 

 a reducing substance. 



In the cornea of oxen His found 758.3 p. m. water, 203.8 p. m. 

 gelatin forming substance, 28.4 p. m. other organic substance, 

 besides 8.1 p. m. soluble and 1.1 p. m. insoluble salts. 



