FIBROUS CONNECTIVE TISSUE. 



65 



PREPARATION C. 



Here the method of preparing collagen was somewhat 

 different from that followed in the two preceding cases. Ox 

 tendons, carefully cleaned and cut into thin transverse sections 

 with a razor (800 grams), were extracted thoroughly with 

 water, then soaked in half-saturated lime-water for three 

 days, for the removal of the mucin. The residual tissue was 

 washed with water and again extracted with lime-water as 

 before. After this treatment the tissue was washed repeatedly 

 for five days with water slightly acidified with acetic acid, 

 care being taken to avoid adding enough acid to cause swell- 

 ing of the fibrous tissue. It was then digested with alkaline 

 pancreatic juice at 40 C., 2.3 liters of an active solution of 

 trypsin containing 0.25 per cent of sodium carbonate being 

 employed. After five days' treatment of this kind the residual 

 collagen was strained off, washed repeatedly with cold water 

 until entirely free from alkaline reaction, after which it was 

 converted into gelatin by the method already described, and 

 further purified as detailed under Preparation A. 



Analysis of the product, dried at 110 C. until of constant 

 weight, gave the following results : 



I. 0.3504 gram substance gave 0.6434 gram C0 2 = 50.07 per cent C, and 



0.2086 gram H 2 O = 6.61 per cent H. 

 II. 0.5127 gram substance gave 0.9390 gram C0 2 = 49.94 per cent C. 



III. 0.3711 



IV. 0.1825 

 V. 1.1582 



VI. 1.3220 



VII. 0.6631 



VIH. 0.5881 



IX. 0.2548 



0.06601 " N- 17.78 " N. 



0.03245 " N = 17.78 " N. 



0.0206 " BaSO 4 = 0.243 per cent S. 



0.0172 " BaSO 4 = 0.177 " S. 



0.0107 " BaS0 4 = 0.221 " S. 



0.0017 " ash = 0.289 per cent ash. 



0.0009 " ash = 0.353 " ash. 



COMPOSITION or THE ASH-FHEE SUBSTANCE. 

 (Average ash = 0.321 per cent.) 



