438 HEPBURN— BIOCHEMICAL STUDIES 



sulphuric acid. For the third time, 10 cc. of albumin solution were 

 placed in the pitcher, and its protein was also digested. It should be 

 noted that a portion of the nitrogen, found in the liquor after the albumin 

 had been digesting for a week, was due to the enzyme and to the chitin 

 of insects. 



Digestion also took place in the pitcher of Nepenthes coccinea. In but 

 two instances was peptone found in the pitchers after digestion of 

 albumin, once with a plant of Nepenthes coccinea, and once with a plant 

 of Nepenthes from Borneo similar to N . phyUamphora. The peptone, 

 it is stated, is diffusible, and probably is absorbed. 



Clautriau classified the protease of the pitcher liquor as a pepsin, 

 since it acted only in an acid medium, and formed true peptone as the 

 ultimate product of its action. Leucine, tyrosin, and other crystalline 

 compounds were not found among the product? of proteolysis. 



An amber color, becoming red with alkali, was. very frequently noted 

 in the liquor after digestion. It w^as ascribed to the presence of tannin 

 derived from the glands, and not to the presence of tryptophan. 



The pitcher liquor did not contain an amylase, for it had no action 

 on starch paste, when the mixture of liquor and paste was digested for 

 5 days. 



Stimulation was found necessary to excite an abundant secretion of 

 both the acid and the protease. The glands, which secrete both the acid 

 and the enzyme, are said to absorb the digested protein. The micro - 

 chemical reactions of the proteins were more intense in the region of the 

 glands, hence it was concluded that the peptone was absorbed by the 

 glands and stored as protein. 



Since the liquor, obtained from healthy pitchers of Nepenthes mel- 

 amphora in its natural habitat, failed to produce proteolysis in vitro, it 

 was suggested by Clautriau that the pitchers of this variety possibly 

 absorb either albumin or albumose. He also pointed out that, if too 

 many insects accumulate in a pitcher, they may be decomposed by 

 bacteria without injury to the plant, which probably utilizes the ammonia 

 and amino acids formed by the bacteria. 



Clautriau looked on the digestion in the pitcher as a source of nitrogen, 

 and possibly of mineral food, for the nutrition of the plant. 



Fenner (13) used Nepenthes Rafflesiana Jack in his study of the pro- 

 teolysis in the pitchers of Nepenthes. He states that the innumerable 

 glands of the pitcher lie in niches which open downwards, and are from 

 one-half to two- thirds covered by a projecting, roof-like, epidermal 

 structure. Wet insects, climbing up the wall to escape from the pitcher, 



