OF INSECTIVOROUS PLANTS 437 



ammonium sulphate, first while acid, then while alkaline in reaction; the 

 resulting solution was permitted to stand; and the albumoses (proteoses) 

 collected, and were removed by filtration. In the filtrate, the ammonium 

 sulphate was removed by means of barium carbonate, and the excess 

 of barium was removed with sulphuric acid. The solution was then 

 filtered and concentrated; it contained no albumose, for it did not form 

 a precipitate with potassium mercuric iodide, or with acetic acid and 

 potassium f errocyanide ; it contained peptone, for it responded to the 

 biuret test, and gave precipitates with tannin, phosphotungstic acid, 

 and phosphomolybdic acid. 



The liquor in a pitcher of Nepenthes Mastersiatia, containing insects, 

 was filtered and used in digestion experiments m vitro. Three cc. of 

 the liquor and 20 drops of albumin (egg-white) solution, prepared as 

 described above, were permitted to react for 3 days, with and without 

 the addition of 1 drop of hydrochloric acid (1 drop contained 0.01 gram 

 of hydrochloric acid), in the presence of camphor as a bactericide. The 

 albumin was completely digested to peptone in both the presence and the 

 absence of the hydrochloric acid, while a blank experiment, heated for 

 10 minutes at 100° C. at the beginning of the experiment, contained no 

 peptone. The digestion in vitro by the liquor plus hydrochloric acid 

 was far more rapid at 37° C. than at 20° C. 



Experiments were made in vitro with the liquor of non-stimulated 

 (unopened) pitchers of Nepenthes coccinea and of a Nepenthes similar to 

 iV. phyllamphora. Albumin was the substrate, and hydrochloric acid 

 was added. After digestion in the incubator for 5 or 6 days, syntonin 

 and a little albumose were present, but no peptone, and enzyme action 

 probably had not taken place. However, Clautriau hesitated to advance 

 the proposition that the secretion of the enzyme, like that of the acid, 

 is the result of stimulation, although the two experiments were con- 

 cordant. 



The products of proteolysis were rapidly absorbed by the pitcher. 

 Successive and abundant additions of albumin were supported perfectly, 

 without inconvenience. In four days, the pitcher of Nepenthes Master- 

 siana, mentioned above, digested 2.5 cc. of albumin solution, and com- 

 pletely absorbed the products. Then 10 cc. of albumin solution (nitrogen 

 content determined by the Kjeldahl method as ammonia equalled 

 14 cc. of 0.1 N sulphuric acid) were introduced into the pitcher; 7 days 

 later the liquor contained nitrogen equal to but 2.8 cc. of 0.1 iV sulphuric 

 acid. Another 10 cc. portion of albumin solution was added; at the end 

 of 7 days the nitrogen content of the liquor equalled but 2.7 cc. of 0.1 N 



