Cuar. VLJ DIGESTION. 77 
head albumen, showing that the secretion loses its power 
when neutralised by an alkali, and recovers it when an acid 
is added. 
Substances which are completely or partially Digested by the 
Secretion of Drosera. 
Albumen.—After having tried various substances, Dr. Burdon 
Sanderson suggested to me the use of cubes of coagulated 
albumen or hard-boiled egg. I may premise that five cubes 
of the same size as those used in the following experiments 
were placed for the sake of comparison at the same time on 
wet moss close to the plants of Drosera. The weather was 
hot, and after four days some of the cubes were discoloured 
and mouldy, with their angles a little rounded; but they 
were not surrounded by a zone of transparent fluid as in the 
case of those undergoing digestion. Other cubes retained 
their angles and white colour. After eight days all were 
somewhat reduced in size, discoloured, with their angles 
much rounded. Nevertheless in four out of the five speci- 
mens, the central parts were still white and opaque. So 
that their state differed widely, as we shall see, from that of 
the cubes subjected to the action of the secretion. 
Experiment 1.—Rather large cubes of albumen were first tried; 
the tentacles were well inflected in 24 hrs; after an additional day the 
angles of the cubes were dissolved and rounded ;* but the cubes were 
too large, so that the leaves were injured, and after seven days one 
died and the others were dying. Albumen which has been kept for 
four or five days, and which, it may be presumed, has begun to decay 
slightly, seems to act more quickly than freshly boiled eggs. As the 
latter were generally used, I often moistened them with a little saliva, 
to make the tentacles close more quickly. 
Experiment 2.—A cube of 3 of an inch (i.e. with each side +1, of an 
inch, or 2°54 mm., in length) was placed on a leaf, and after 50 hrs. it 
was converted into a sphere about -$ of an inch (1:905 mm.) in 
diameter, surrounded by perfectly transparent fluid. After ten days 
* In all my numerous experi- 
ments on the digestion of cubes of 
albumen, the angles and edges were 
invariably first rounded. Now, Schiff 
states (‘ Leçons Phys, de la Digestion,’ 
1867, tom. ii. p. 149) that this is 
characteristic of the digestion of 
albumen by the gastric juice of 
animals, On the other hand, he 
remarks, ‘ les dissolutions, en chimie, 
ont lieu sur toute la surface des corps 
en contact avec l'agent dissolvant.” 
