1893.] Recent Studies of Carnivorous Plants. 417 
of peptonizing egg albumen only after it had passed from 
neutral to acid reaction. He further says that it is extremely 
improbable that this peptonizing principle is secreted by the 
glands of the Nepenthes pitchers, but that it is produced by 
certain micro-organisms present in the solution. Hence the 
digestion that takes place is not analogous to digestion of 
albuminoids in the stomach of man, because in the latter case 
the secretion of gastric juice follows as a result of direct 
irritation. 
To demonstrate this more fully he repeated his experiments 
in a modified form, using a neutral secretion which contained 
no bacteria. For this purpose he selected two unopened cups 
of Nepenthes coccinea and Nepenthes—sp. ?——which were so far 
developed that the liquid was already present in considerable 
quantity. The leaves were separated from the plant and the 
petioles were attached to a ring stand so that the pitcher of 
the leaf was vertical. The outside of each pitcher was disin- 
fected with a freshly prepared 1:1000 sublimate solution in 
water. After the water of the sublimate solution had par- 
tially evaporated, a small hole 3 mm. in diameter was cut in 
the wall of the pitcher with a pair of sterilized scissors. The 
secretion from each was then transferred by means of a steril- 
ized pipette into two test tubes each containing two cubic 
centimeters of distilled water and a small cube of coagulated 
egg albumen. One of the test tubes was slightly acidulated 
with hydrochloric acid, the other remained neutral. The four 
test tubes were then placed in a thermostat at 37.5° C. 
At the end of 48 hours there wasno solution of the egg 
albumen, though a control experiment with a test tube con- 
taining pepsin gave positive results. Microscopic examination 
and gelatine cultures gave negative results. These experi- 
ments were repeated, using the remainder of the secretion 
diluted with a little pure glycerin, but the result was the 
same. 
In these experiments the only question that could be raised 
was whether the pitchers from which the secretion was taken 
were not too young to contain pepsin. But if one remembers 
the experiments of Wunschmann in 1872, and also considers 
