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548 TISSUES OF THE CONNECTIVE SUBSTANCE.
more strongly than glucose. 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
acid and glucosamine. This assumption does not seem to have sufficient
foundation. According to Orgler and Neuberg, chondrosin does not
give the orcin test nor does it yield furfurol. They claim that on
cleavage with baryta it yields, besides a carbohydrate complex which
has not been studied, an oxyamino-acid having the formula C6H13O6N,
a hexosamine acid or tetraoxyaminocaproic acid. In opposition to this
S. Frankel has found that the chondrosin gives the orcin as well as the
phloroglucin test with hydrochloric acid, and he has prepared an acid
with the formula CeHnNOe, which he calls aminoglucuronic acid,
which gives the above tests and also reduces. Among other investi-
gators, Pons and Kondo l
have also found that chondroitin-sulphuric
acid gives the orcin test and yields furfurol, according to Pons 6.6-6.9
per cent. The chondrosin obtained after boiling with acid and distilling
off the furfurol does not, according to Pons, give furfurol, which agrees
with Orgler and Neuberg’s statement. From the hydrolytic products
of chondroitin-sulphuric acid with hydrochloric acid, Pons obtained
with phenylhydrazin. a crystalline substance melting at 143° C.
Chondroitin-sulphuric acid appears as a white amorphous powder
which dissolves very easily in water, forming an acid solution and, when
sufficiently concentrated, a sticky liquid similar to a solution of gum
arabic. Nearly all of its salts are soluble in water. The neutralized
solution is precipitated by stannous chloride, basic lead acetate, neutral
ferric chloride, and by alcohol in the presence of a little neutral salt.
The solution, on the other hand, is not precipitated by acetic acid,
tannic acid, potassium ferrocyanide and acetic acid, sugar of lead, mer-
curic chloride, or silver nitrate. Acidified solutions of alkali chondroitin-
sulphates cause a precipitation when added to solutions of gelatin or
proteid.
The preparation of chondromucoid, and its separation from chondroitin-
sulphuric acid can be accomplished after the method of C. Morner, but for
details we refer to the original work.
The pre-existing chondroitin-sulphuric acid, or that formed by the
decomposition of chondromucoid, is obtained by lixiviating the cartilage
with a 5-per cent caustic-alkali solution. The alkali albuminate formed
by the decomposition of the chondromucoid can be removed from the
solution by neutralization, then the peptone precipitated by tannic acid,
1
Orgler and Neuberg, Zeitschr. f. physiol. Chem., 37; Frankel, Annal. d. Chem. u.
Pharm., 351; Pons. Arch, intern, de Physiol., 8 (1909); Kondo, Bioch. Zeitschr., 26.
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