CLEA VAGE THEOR Y OF PROTEID DIGESTION. 407 



Now washed with water until no reaction for chlorides was obtained, and 

 afterwards treated with alcohol and ether, it formed a powder of slightly 

 yellowish colour. A part of this purified antialbumid was dissolved in sodium 

 carbonate solution of '5 per cent., and treated with a dialysed and very active 

 trypsin solution at 37-38 C. After thirty minutes the mixture began to be 

 turbid, and in two hours solidified to a clot. By breaking up the clot and 

 filtering, the fluid part was separated from the clot; it was made scarcely 

 turbid by neutralisation, and yielded by further digestion no new precipitate, but 

 contained a fair amount of peptone. 



The separated clot was soluble in hydrochloric acid of 2 per mille, but as 

 insoluble in sulphuric acid of 4 per mille as the original precipitate. It was 

 completely precipitated from solution in 1 per cent, sodium carbonate solution 

 by concentrated sodium chloride solution. From this it seems that in the 

 coagulation of albumid in trypsin no change takes place other that its becom- 

 ing more insoluble in sodium carbonate solution. The action of trypsin in 

 more alkaline solution was next tried; after the first precipitation of the 

 albumid it was dissolved in '75 per cent, sodium carbonate solution, digested 

 with dialysed tryptic fluid, neutralised and filtered. The clotlike albumid was 

 dissolved in 5 per cent, sodium carbonate solution, and by repeated digestion 

 with dialysed tryptic fluid, the greater portion was converted into antipeptone. 

 The final residue from this much accentuated tryptic digestion was completely 

 insoluble even in 5 per cent, sodium carbonate solution, but dissolved in 1 per 

 cent, caustic soda. Precipitated by neutralising with hydrochloric acid, 

 washed, redissolved in sodium carbonate, and treated with trypsin anew, it was 

 again completely thrown out as a clotlike coagulation. No leucine or tyrosine 

 was present in the tryptic filtrates. 



How widely this account differs from the statement which occurs in 

 most text-books, that antialbumid is not attacked by pepsin, but is 

 converted into antipeptone by trypsin, may easily be seen. In a fluid of 

 equal alkalinity to that found in the body, antialbumid is no more 

 digested by trypsin than it is by pepsin and hydrochloric acid. Now 

 it has been shown that trypsin is most active in a sodium carbonate 

 solution of about 1 per cent., 1 and considerably less active in one of 5 

 per cent. ; why then does trypsin in 5 per cent, solution do that which it 

 is unable to do in 1 per cent, solution ? Obviously because the 5 per 

 cent, solution dissolves the clot of antialbumid, while the 1 per cent, 

 solution does not. In the former case a weaker trypsin acts on anti- 

 albumid in solution ; in the latter, a stronger trypsin on antialbumid as 

 an insoluble precipitate. 



Be this as it may, antialbumid is only with great difficulty and 

 incompletely peptonised by trypsin. In all its properties, from its mode 

 of formation onward, the substance appears to be merely a very insoluble 

 form of acid albumin. 



Antialbumose. By a fractionated peptic digestion, Kuhne and 

 Chittenden 2 obtained a substance which they termed antialbumose. 

 The preparation of this substance from white of egg is as follows : 



The white of fifty eggs was freed from membrane, diluted and coagulated 

 by boiling after acidifying with acetic acid. The coagulated proteid was 

 digested in two litres of 4 per mille hydrochloric acid and one litre of dialysed 

 gastric extract for one and a half hours at 40 C., it was then allowed to cool 

 to the temperature of the room and filtered from the undissolved part, the 

 process of filtration occupying two days. The undissolved residue was again 

 treated with fresh gastric extract until it was all dissolved, which occupied 

 1 See p. 338. 2 Loc. cit., p. 171. 



