PROTEIN REGENERATION 29 



mesenteric vein there was no increase in the glycogen of the liver, but 

 that an actual excretion of sugar from the blood into the lumen of the 

 intestine occurred. He held that the experiments of Grube, who 

 showed that perfusion of the tortoise liver with dextrose could give 

 rise to glycogen, were without value as they were carried out on a 

 cold-blooded animal. Pfltiger, it may be noted, held that this objection 

 was not valid. Fischer and Moore (128) have also observed this 

 excretion of carbohydrate into the intestine, but the conditions under 

 which it occurs are more or less pathological. 



Plastein Formation. 



Intimately connected with the preceding work on protein regenera- 

 tion are the curious observations on the so-called plastein formation. 

 This work originated in the experiments of Danilevsky and Okuneff in 

 1895 (107), who showed that if rennin were brought into contact with a 

 solution of proteoses a precipitate plastein was produced. They 

 regarded this precipitate as a resynthetized protein. Kurajeff (235) 

 observed the same formation of a precipitate when papayotin solutions 

 were brought into contact with proteose solutions. In a later communi- 

 cation (235) he stated that he could obtain the formation of a coagulable 

 protein from his plastein proteoses, if they were brought into contact with 

 the gastric or intestinal mucous membrane. Nurnberg (306) found 

 that the plastein formation was not limited directly to the action of 

 the gastric rennin, for if autolytic organic extracts were brought into 

 contact with protein solutions a precipitation resulted. This work was 

 confirmed by that of Grossmann (159). Sawjaloff (354) also investi- 

 gated this precipitation reaction. He came to the conclusion that the 

 digestion in the gastro-intestinal canal formed a substance which, taken 

 up into the circulation, was coagulated later when and where re- 

 quired. He stated that if the proteose solution were fractionated in 

 the manner described by Pick, and if the individual fractions were then 

 treated with the enzyme, no precipitation resulted, although the same 

 proteose solution not fractionated gave the precipitation quite readily. 

 He was firmly convinced that the reaction was a true synthetic one. 

 He further held that the substance formed was a true substance of 

 constant constitution. He gave to the substance the name plastein. 



On the other hand, Lavroff and Salaskin (245) held that there was 

 no reason why the precipitate should be accepted as an entity a re- 



