PAPAIN-PROTEOLYSIS. 173 



in the present experiment, the element of time is of less mo- 

 ment. In other words, when the ratio of enzyme to proteid 

 is suitable, the maximum digestive action under those condi- 

 tions is reached in 24-48 hours, and longer exposure at 40 C. 

 fails to increase the proportion of peptone formed. In illus- 

 tration of this point compare the results of the first and third 

 experiments. In conclusion we think it clearly established 

 that papain is not only a peptone-forming enzyme, but that 

 under proper conditions it is able to transform a large propor- 

 tion of the proteid matter into true peptone. In confirmation 

 of this statement we have been able to prepare and isolate the 

 pure peptone in quantity sufficient to study some of its physi- 

 ological properties. 



SOME OBSERVATIONS ON THE PHYSIOLOGICAL ACTION OF 

 THE DEUTEROALBUMOSE AND PEPTONE FORMED BY PAPAIN. 



It has been generally believed for some time past that the 

 primary products which result from the proteolytic action of 

 vegetable enzymes, as well as those formed by the action of 

 superheated water, are somewhat different in nature from the 

 corresponding products formed by pepsin-acid and by trypsin. 

 Thus Neumeister * has shown that if atmid albumin or atmid 

 albumose, i. e., the albumose formed by the action of super- 

 heated water on blood-fibrin, is injected directly into the blood 

 of a dog it appears in the urine wholly unaltered. An ordin- 

 ary albumose, however, i. ., such as is formed by pepsin or 

 trypsin, when introduced into the circulation (of a dog) ap- 

 pears in the urine more or less hydrated.f Thus, protoalbu- 

 mose appears in the urine in part as deuteroalbumose, while 

 if deuteroalbumose is injected into the blood it appears in the 

 urine as peptone. Peptone, on the other hand, is eliminated 

 wholly unchanged. Neumeister | also makes the statement 



* Neumeister, Ueber die nachste Einwirkung gespannter Wasserdampfe 

 auf Proteine und iiber eine Gruppe eigenthiimlicher Eiweisskorper und 

 Albumosen. Zeitschr. f. Biol., 1890, xxvi, p. 77. 



t Neumeister, Ueber die Einfiihrung der Albumosen und Peptone in den 

 Organismus. Ibid., 1888, xxiv, p. 272. 



t Neumeister, Ibid., xxvi, p. 82. 



