82 DROSERA ROTUNDIFOLIA. [Cuap. VI. 
On three other occasions eight leaves were strongly ex- 
cited with albumen moistened with saliva; they were then 
cut off, and allowed to soak for several hours or for a whole 
day in a few drops of glycerine. Some of this extract was 
added to a little hydrochloric acid of various strengths 
(generally one to 400 of water), and minute cubes of albumen 
were placed in the mixture.* In two of these trials the 
cubes were not in the least acted on; but in the third the 
experiment was successful. For in a vessel containing two 
cubes, both were reduced in size in 3 hrs; and after 24 hrs. 
mere streaks of undissolved albumen were left. In a second 
vessel, containing two minute ragged bits of albumen, both 
were likewise reduced in size in 3 hrs. and after 24 hrs. com- 
pletely disappeared. I then added a little weak hydro- 
chloric acid to both vessels, and placed fresh cubes of 
albumen in them; but these were not acted on. This latter 
fact is intelligible according to the high authority of Schiff,t 
who has demonstrated, as he believes, in opposition to the 
view held by some physiologists, that a certain small amount 
of pepsin is destroyed during the act of digestion. So that 
if my solution contained, as is probable, an extremely small 
amount of the ferment, this would have been consumed by 
the dissolution of the cubes of albumen first given: none 
being left when the hydrochloric acid was added. The 
destruction of the ferment during the process of digestion, or 
its absorption after the albumen had been converted into a 
peptone, will also account for only one out of the three latter 
sets of experiments having been successful. 
Digestion of Roast Meat.—Cubes of about -y of an inch 
(1:27 mm.) of moderately roasted meat were placed on five 
leaves which became in 12 hrs. closely inflected. After 48 
hrs. I gently opened one leaf, and the meat now consisted of 
a minute central sphere, partially digested and surrounded 
by a thick envelope of transparent viscid fluid. The whole, 
fact would lead us to believe that the 
act of secretion in Nepenthes is pre- 
ceded by the production of a mother 
substance, or pepsinogen, from which 
the peptic ferment is formed by ac- 
tion of acid—just as the pancreatic 
ferment may, according to Heidenhain, 
be produced by the action of acid on 
zymogen—F, D.] 
* As a control experiment bits of 
albumen were placed in the same 
glycerine with hydrochloric acid of 
the same strength ; and the albumen, 
as might have been expected, was 
not in the least affected after two 
days. 
t ‘Leçons phys. de la Digestion,’ 
1867, tom. ii, pp. 114-126. 
