THE PRODUCTS OF TRYPTIC DIGESTION. 195 



Antipeptone. To prepare antipeptone in amounts which are 

 sufficient for the purpose of isolating the hexon bases which the sub- 

 stance supposedly contains, it is necessary to start with a large quantity 

 of fibrin : 1000 grammes of the latter are suspended in 2000 c.c. of 

 an 0.25 per cent, solution of sodium carbonate, to which a few 

 grammes of an active pancreatin preparation have been added. 

 Putrefaction is prevented by adding an amount of chloroform suffi*- 

 cient to saturate the solution, as also a few crystals of thymol. The 

 mixture is thoroughly shaken and kept at a temperature of 40 C. 

 for at least one week. It is then filtered, slightly acidified with 

 acetic acid, boiled, again filtered, and concentrated to about 1000 c.c. 

 On cooling, a good deal of tyrosin separates out and is filtered off. 

 The filtrate is diluted with water to about 2000 c.c., neutralized, 

 heated to near the boiling-point, and saturated with ammonium sul- 

 phate in substance. On cooling, any albumoses that may have sepa- 

 rated, together with a large quantity of the salt, are filtered oiF. The 

 filtrate is heated, and while boiling rendered strongly alkaline with 

 ammonia and ammonium carbonate, and again saturated with ammo- 

 nium sulphate. On cooling, a second fraction of albumoses is filtered 

 off. The solution is then heated until the odor of ammonia has dis- 

 appeared ; ammonium sulphate is again added to saturation, and the 

 liquid rendered distinctly acid with acetic acid, when on cooling a 

 third fraction of albumoses separates out and is filtered off. The 

 filtrate is concentrated to about one liter and freed from a large 

 amount of ammonium sulphate, which separates out on cooling. It 

 is then diluted with water to about 3000 c.c., and treated at a tem- 

 perature of 30 C., with barium hydrate in substance, to remove 

 the remaining salt. A slight excess of the barium is removed with 

 carbonic acid, and is filtered off after boiling for a moment. The 

 filtrate is evaporated to about 1000 c.c., when the barium peptone is 

 decomposed with dilute sulphuric acid, care being taken that the 

 acid is not added in excess. The resulting barium sulphate 

 is filtered off and the filtrate concentrated to a thin syrup. On cool- 

 ing, absolute alcohol is added until the turbidity that first appears 

 no longer disappears on stirring. After filtering with the aid of a 

 suction pump, the solution is poured into absolute alcohol while 

 stirring. The antipeptone is then precipitated and allowed to settle, 

 when the supernatant fluid is siphoned off and the antipeptone col- 

 lected on a filter with the aid of a suction-pump. It is finally 

 washed with absolute alcohol, then with ether, and rapidly placed in 

 a desiccator over sulphuric acid. 



From this material Kutscher claims that the three hexon bases 

 can then be isolated. To demonstrate that these bodies actually 

 result from the albumins on hydrolytic decomposition, it is more con- 

 venient, however, to effect this by boiling with dilute acids. To 

 this end, commercial gelatin is conveniently utilized as a starting 

 material, as larger amounts of arginin at least can thus be obtained. 

 The method, however, is quite complicated and scarcely requires 

 consideration at this place. 



