226 ANTI-PEPTONE. [BOOK II. 



that in the absence of bacteria there is, during prolonged digestion 

 by trypsin, an absorption of oxygen from the surrounding medium 

 (as from the air of the flask in which the digestion is carried on) 

 and a development of CO 2 , the amount of this gas evolved being 

 however very small. We shall afterwards draw attention to the 

 results of Nencki's 1 observations on the gases formed during 

 pancreatic digestion associated with putrefaction. 



We have now to study in succession the chief products of the 

 action of trypsin on proteids. 



SECT. 8. ANTI-PEPTONE RESULTING FROM THE ACTION OF 

 TRYPSIN (SYN. TRYPTONE). 



Our knowledge of the mode of preparation, composition and 

 reactions of anti-peptone, the product of the prolonged action of 

 trypsin acting in an alkaline medium, at a suitable temperature, is 

 based entirely on the researches of Kiihne, and of Kiihne and 

 Chittenden. The most recent information concerning anti-peptone is 

 contained in a paper to which reference has already frequently been 

 made in the preceding pages 2 . 



Modeofpre- Blood-fibrin is the most convenient proteid to 

 paration of employ in the preparation of anti-peptone, or indeed 

 anti-peptone in general whenever the chief products of decomposition 

 from blood- O f the proteids by trypsin are to be studied. 



In his experiments Ktihne took well-washed blood- 

 fibrin, boiled it in water, then in alcohol, and extracted it with ether. 

 The fibrin which had thus been purified was again boiled in water 

 and then subjected to the digestive process. 



In his earlier researches on pancreatic digestion, Kiihne prevented 

 the onset of putrefaction by employing an extract of pancreatic 

 gland made by digesting the pancreas in a solution of salicylic acid. 

 Thus in one experiment he digested 800 grms. of pancreas at 40 C. 

 in 2 litres of water containing 4 grms. of salicylic acid, and employed 

 the solution of ferment thus obtained to effect the digestion of large 

 quantities of fibrin. 



In his more recent experiments, in association with Chittenden, 

 Kiihne has carried on his digestions with the aid of extracts of 

 pancreas which, mutatis mutandis, were made essentially in the 

 manner described at page 222 ; viz. by first digesting pancreas 

 which had been dehydrated and freed from fat by treatment with 

 alcohol and ether, in O'l per cent, solution of salicylic acid, and after- 

 wards digesting the undissolved residue of the gland in 0*25 per cent, 

 solution of sodium hydrate to which thymol had been added. 



1 Nencki, ' Ueber die Zersetzung der Gelatine und des Eiweisses bei der FaiilmBS 

 mit Pancreas.' Maly's Jahresbericht, Vol. vi. (1876), p. 31. 



2 Kiihne and Chittenden, ' Ueber die Peptone.' Zeitschrift flir Biologie, Vol. xxn. 

 (1886), see p. 434 et seq. 



