522 TISSUES OF THE CONNECTIVE SUBSTANCE. 



quantities of mineral acids. The precipitation may be retarded by 

 neutral salts or by chondroitin-sulphuric acid. The solution containing 

 NaCl and acidified with HC1 is not precipitated by potassium ferro- 

 cyanide. Precipitants for chondromucoid are alum, ferric chloride, sugar 

 of lead, or basic lead acetate. Chondromucoid is not precipitated by 

 tannic acid, and it may by its presence prevent the precipitation of 

 gelatin by this acid. It gives the usual color reactions for proteins, 

 namely, with nitric acid, with copper sulphate and alkali, with MILLON'S 

 and ADAMKIEWICZ'S reagents. 



Chondroitin-sulphuric Acid, CHONDROITIC ACID. This acid, which was 

 first prepared pure, from cartilage, by C. MORNER and identified by him 

 as an ethereal sulphuric acid, occurs, according to MORNER, in all varie- 

 ties of cartilage and also in the tunica intima of the aorta and as traces 

 in the bone substance. K. MORNER 1 has also found it in the ox-kidney 

 and in human urine as a regular constituent. Its occurrence in amyloid 

 as mentioned on page 168 has been disputed by HANSSEN. In the 

 opinion of LEVENE, 2 the glucothionic acid which is prepared from tendon 

 mucoid and which gives the orcin reaction for glucuronic acid, and yields 

 furfurol on distillation with hydrochloric acid, is not identical with the 

 chondroitin-sulphuric acid, but is probably related thereto. 



Chondroitin-sulphuric acid has the formula Ci 8 H 27 NSOi 7 , according 

 to ScHMiEDEBERG. 3 As primary products this acid yields, on cleavage, 

 sulphuric acid and a nitrogenous substance, chondroitin, according to 

 the following equation : 



Chondroitin, which is similar to gum arabic, and which is a monobasic 

 acid, yields acetic acid and a new nitrogenous substance, chondrosin, 

 as cleavage products, on decomposition with dilute mineral acids: 



Chondrosin, which is also a gummy substance soluble in water, is a 

 monobasic acid and reduces copper oxide in alkaline solutions even 

 more strongly than dextrose. It is dextrogyrate, and represents the 

 reducing substance obtained by previous investigators in an impure 

 form on boiling cartilage with an acid. The products obtained on decom- 

 posing chondrosin with barium hydroxide tend to show, according to 

 SCHMIEDEBERG, that chondrosin contains the atomic groups of glucuronic 



1 C. Morner, 1. c., and Zeitschr. f. physiol. Chem., 20 and 23; K. Morner, Skand. 

 Arch. f. Physiol., 6. 



2 Zeitschr. f. physiol. Chem., 39. 



3 Arch. f. exp. Path. u. Pharm., 28. 



