FIBROUS CONNECTIVE TISSUE. 63 



collagen was boiled with a fresh quantity of distilled water, 

 this operation being repeated until the larger part of the 

 collagen was transformed into gelatin. The united fluids 

 were then evaporated on the water-bath until quite concen- 

 trated, forming when cold a hard, firm jelly. The gelatin 

 was next precipitated by alcohol, this being accomplished by 

 pouring the warm jelly, with stirring, into a large volume of 

 95 per cent alcohol, by which it was thrown down as a soft 

 stringy mass, gradually hardening by longer contact with the 

 alcohol. The precipitate was then extracted for some days 

 with absolute alcohol, and then with ether until it became 

 hard and brittle. It was next ground up in a mortar, and 

 the powder extracted continuously for two days with ether, 

 for the complete removal of all fat or other ether-soluble 

 matter. After this treatment the gelatin was dissolved in 

 hot water, the fluid filtered through paper with the aid of a 

 hot-water funnel, the filtrate concentrated somewhat, and 

 again precipitated by a large volume of alcohol. The pre- 

 cipitate was dehydrated by repeated treatment with absolute 

 alcohol, again pulverized and re-extracted with ether, after 

 which it was considered ready for analysis. 



For analysis, a sufficient amount of the substance was dried 

 at 110 C. until of constant weight. Carbon and hydrogen 

 were determined by combustion in an open tube with oxygen 

 gas, the products of combustion passing over a layer of cupric 

 oxide, a layer of lead chromate, and a roll of reduced copper. 

 Nitrogen was determined by the Kjeldahl method, sulphur by 

 fusion with sodium hydroxide and potassium nitrate in a 

 silver crucible and precipitation as barium sulphate after the 

 method recommended by Hammarsten.* 



Following are the results obtained : 



PREPARATION A. 



I. 0.5359 gram substance gave 0.9818 gram C0 a = 49.96 per cent C, and 



0.3203 gram H 2 O = 6.64 per cent H. 



IL 0.3622 gram substance gave 0.6615 gram C0 2 = 49.87 per cent C, and 

 0.2145 gram H 2 = 6.57 per cent H. 



* Zeitschr. f. physiol. Chemie, Bd. ix, p. 289. 



