179 



158 F., pancreatin is destroyed; pepsin at about l6o F. Quite the 

 reverse is the influence upon the papaw ferments. Here the action, 

 beginning as low as 50 or 60 F., increases slightly with the rise of 

 temperature until between 155-160 F. it reaches the maximum. 

 The action is not entirely destroyed even at a few moments' ex- 

 posure at the boiling point. A digestive ferment active at tem- 

 peratures ranging from 50 F. to the boiling point is notable. 



PRODUCTS OF DIGESTION BY THE PAPAW FERMENT. 



A peculiar phenomenon arises in the digestion of albumen by 

 the papaw enzyme. It is particularly noticeable in the digestion 

 of egg albumen in alkaline solution, but it is manifest in the di- 

 gestion of raw flesh albumen in either acid, neutral or alkaline 

 media. After every prolonged digestion there is found an undis- 

 solved residue, which many observers have characterised as an un- 

 changed albumen, and which is usually measured as undigested 

 residue. But such is not the case. This residue is an altered al- 

 bumen ; is soluble in o'S to O'S per cent, solution of sodium carbo- 

 nate or 0-2 per cent, hydrochloric acid. From such solution it is 

 reprecipitated upon neutralization, and re-dissolved by an excess of 

 the precipitant. It is insoluble in salt solutions. Its solution in 

 sodium carbonate upon dialysis becomes almost entirely soluble in 



water. 



The dialysed solution noted above gives a precipitate with acetic 

 acid and potassium ferrocyanide, but nitric acid gives no precipi- 

 tate. The solution gives the ordinary proteid reactions, and ap- 

 parently the whole of the proteids are reprecipitated by the addi- 

 tion of a large quantity of alcohol. This body is further digested 

 after washing and treatment with a fresh solution of the ferment, 

 and also in an acid solution of pepsin ; it is almost completely di- 

 gested in an alkaline solution of trypsin, yielding (as shown at one 

 trial) the ordinary products of digestion. This body corresponds 

 quite closely to the antialbumid found in digestions by hydrochloric 

 acid and by trypsin.* 



The products arising in the digestion of egg albumen, blood 

 fibrin or beef albumen are quite alike either in acid, alkaline or 

 neutral solutions, with the exception of certain slight modifica- 

 tions dependent upon the conditions of trial, reaction, etc. He- 

 mialbumose (protoalbumose, deuteroalbumose and, in some in- 

 stances, heteroalbumose), hemipeptone, peptone products, and the 

 amid bodies, leucin and tyrosin, are all found in addition to the 

 peculiar body above noted which is present only in minute 

 amounts. 



All of these bodies seemingly make their appearance in the 

 early stages of digestion, and each one is found at the end of pro- 

 longed digestion, although under ordinary circumstances deuteroal- 

 bumose and true peptone predominate to a high degree. 



* A (luite similar bofij- is louml in Brometin digestion of albumen. (See Chitten- 

 { en— Journal Physiology No. 4, 1893.) It is quite evident that this body would be re dily 

 converted into soluble absorbable products in the digi stive tract. 



