117 



The amount of residue left after extraction with water may be taken 

 as a rough estimate of the foreign material present, the ferment itself 

 beino- associated with a more or less soluble albumose. A more accu- 

 rate method of estimation as to the amount of ferment-bearing bodies 

 is as follows :— Extract a weighed portion of the powder with water 

 (two or three successive portions with trituration) ; combine the aque- 

 ous solutions and saturate with crystals of magnesium sulphate and 

 sodium sulphate in about equal proportions. If the solution is warmed 

 the precipitate will be quicker. The precipitate thus obtained, freed 

 from salts by dialysis, will consist of albumose and globulin, and the 

 weight of these when dried will give the measure of soluble bodies 

 with which the ferment is associated, or the amount of ferment-bear- 

 ing bodies in the sample. 



In the best of the market preparations which I have examined I 

 have found, in addition to these soluble bodies, insoluble globulins and 

 an appreciable amount of peptone, the latter not being precipitated by 



the foregoing methods. 



Digestive Action. 

 The digestive action of the ferment of the papaw plant has been 

 quite fully described. The actions which are summarized have been 

 made with one of the market ferments sold under the name of " Pa- 



poid."i9 



Papoid is a German production, and, according to the statement of 

 the manufacturers, it is prepared by precipitation from a watery ex- 

 tract of the papaw juice or milk. It consists essentially of globulin 

 and albumoi^e, associated with the ferments, and in addition it contains 

 a small amount of natural inorganic salts. This preparation was used 

 by the writer in a previous communication, and by Chittenden, (See 

 " Papoid Digestion" Transactions of Connecticut Academy, Vol. IX, 



1892.) 



The action of this ferment presents features which contrast pecu- 

 liarly with those of the ordinary digestive ferments. Direct compari- 

 son of the enzyme of the papaw with any other ferment is practically 

 impossible, and this is especially true as to its behaviour in compari- 

 son with the animal ferments. 



The action of most ferments is inhibited by the products of digestive 

 action ; such does not seem to be the effect in the case of the papaw 

 enzyme. It acts in a concentrated solution, even when carrying pro- 

 ducts of its own action. Certain of my experiments tend to show, 

 however, that this enzyme has a notable action in a stream of running 

 water. In other words, its action seems to be continuous, and the 

 ferment is not removed by washing or by the action of fluids in which 

 it is soluble. One such experiment was as follows : — 



Two ounces of raw lean beef were cut into slices, over which was 

 poured an alkaline solution of the papaw ferments. The beef was al- 

 lowed to remain in this solution for half an hour, during which time 

 the solution was fairly well absorbed and the beef somewhat softened. 

 The whole was then wrapped in a filter paper, transferred to a fine 



19 This preparation was used on acconat of its cjuvenionce and because of the 

 lack of sufficient material, separated by the processes outlined in another part of 

 this paper. 



