524 TISSUES OF THE CONNECTIVE SUBSTANCE. 



It is then dissolved in alkaline water and the basic alkali compound 

 precipitated from this solution by the addition of alcohol, whereby the 

 gelatin -peptone alkali remains in solution. The precipitate is purified 

 by repeated solution in alkaline water and precipitated by alcohol. To 

 obtain chondroitin-sulphuric acid entirely free from chondroitin it is 

 more advantageous to prepare the potassium-copper compound of the 

 acid, from the alkaline solution, by the alternate addition of copper acetate 

 and caustic potash and precipitation with alcohol. The reader is referred 

 to the original article for more details and also tor ODDI'S method. 



The collagen of the cartilage gives, according to C. MORNER, a gelatin 

 which contains only 16.4 per cent N" and which can hardly be considered 

 identical with ordinary gelatin. 



In the above-mentioned cartilages of full-grown animals the chon- 

 droitin-sulphuric 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 a trabecular structure, which is colored when brought 

 in contact with tropseolin. 



The albumoid is a nitrogenized body which contains loosely com- 

 bined sulphur. It is soluble with difficulty in acids and alkalies and 

 resembles keratin in many respects, but differs from it by being soluble 

 in gastric juice. In other respects it resembles elastin, but differs from 

 this substance in containing sulphur. This albumoid gives the color 

 reactions of the protein bodies. 



Cartilage gelatin and the albumoid may be prepared according to 

 the following method of MORNER: First remove the chondromucoid 

 and chondroitin-sulphuric acid by extraction with dilute caustic potash 

 (0.2-0.5 per cent), remove the alkali from the remaining cartilage by 

 water, and then boil with water in a PAPIN'S digester. The collagen 

 passes into solution as gelatin, while the albumoid remains undissolved 

 (contaminated by the cartilage-cells). The gelatin may be purified by 

 precipitating with sodium sulphate, which must be added to saturation 

 in the faintly acidified solution, redissolving the precipitate in water r 

 dialyzing well, and precipitating with alcohol. 



In MORNER'S experience no albumoid is found in young cartilage, but 

 only the three first-mentioned constituents. Nevertheless the young 

 cartilage contains about the same amounts of nitrogen and mineral 

 substances as the old. 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 proportion of chondroitin-sulphuric 

 acid and collagen. 



According to PFLUGER and HANDEL, 2 glycogen occurs to a slight 



1 Maly's Jahresber., 19, 325. 



2 Pfluger's in Pfliiger Arch., 92; Handel, ibid. 



