Vines . — Proteolytic Enzyme of Nepenthes (III). 565 
Hence it would appear that the liquid contained no proteid 
matter of any kind. The conclusion at which Clautriau 
arrives is that the introduced albumin is rapidly attacked, and 
that the products of digestion are absorbed as quickly as they 
are formed. The proteolytic action is, moreover, exerted by 
an enzyme secreted by the plant, and is not attributable, as 
Dubois and Tischutkin suggested, to microbes. A further 
observation of special importance is that when a pitcher is 
separated from the plant, digestion is at once arrested. 
In order, if possible, to trace the various stages in the 
proteolytic process, Clautriau instituted a series of ex- 
periments in vitro , the tubes being placed - by the side of 
the plants in the open. In all cases but one, the albumin 
in the tubes underwent no change : in the exceptional case, 
a quantity of albumose, with perhaps some peptone, was 
formed. This negative result he attributes, with considerable 
probability, to the relatively low temperature. Nevertheless 
the experiments are of interest, in that they suggest some 
specific influence of the pitcher upon the digestive process. 
On his return to Europe, Clautriau pursued his researches 
on plants (mostly N. M aster siana) grown in hot-houses. As 
regards digestion in the pitcher itself, he found, as in his 
previous experiments in Java, that although the albumin 
which he introduced disappeared, he could, as a rule, find 
no proteids in the resulting liquid. For example: 15 c.c. 
of a watery solution containing 2*5 c.c. of the incoagulable 
albumin were poured into a pitcher : four days afterwards the 
liquid was found to have been partially absorbed, the re- 
mainder being viscid and amber-coloured, as is usually the 
case after digestion : but it contained no albumin, syntonin, 
albumose, or peptone. However in two such experiments he 
was able to detect the presence of peptone. 
These experiments were supplemented by others in vitro , 
of which the following is a detailed example : 3 c.c. of 
filtered pitcher-liquid were placed in each of three tubes 
A, B, C, and to each 20 drops of a solution of incoagulable 
albumin were added : to B was also added one drop of 
P p 2 
