80 DROSERA ROTUNDIFOLIA. [Cuar. VI. 
was added. Acil of this greater strength was used as the solutions 
of the alkalies were stronger. The process of digestion now com- 
menced, so that within 48 hrs. from the time when the acid was given 
the four cubes were not only completely dissolved, but much of the 
liquefied albumen was absorbed. 
Experiment 11.—lwo cubes of albumen (75 of an inch, or ‘635 mm.) 
were placed on two leaves, and were treated with alkalies as in the last 
experiment, and with the same result; for after 22 hrs. they had their 
angles perfectly sharp, showing that the digestive process had been 
completely arrested. I then wished to ascertain what would be the 
effect of using stronger hydrochloric acid; so I added minute drops of 
the strength of 1 per cent. ‘his proved rather too strong, for after 48 
hrs. from the time when the acid was added one cube was still almost 
perfect, and the other only very slightly rounded, and both were 
stained slightly pink. This latter fact shows that the leaves were 
injured,* for during the normal process of digestion the albumen is 
not thus coloured, and we can thus understand why the cubes were 
not dissolved. 
From these experiments we clearly see that the secretion 
has the power of dissolving albumen, and we further see 
that if an alkali is added, the process of digestion is stopped, 
but immediately recommences as soon as the: alkali is 
neutralised by weak hydrochloric acid. Even if I had tried 
no other experiments than these, they would have almost 
sufficed to prove that the glands of Drosera secrete some 
ferment analogous to pepsin, which in presence of an acid 
gives to the secretion its power of dissolving albuminous 
compounds. 
Splinters of clean glass were scattered on a large number 
of leaves, and these became moderately inflected. They 
were cut off and divided into three lots; two of them, after 
being left for some time in a little distilled water, were 
strained, and some discoloured, viscid, slightly acid fluid was 
thus obtained. The third lot was well soaked ina few drops 
of glycerine, which is well knowa to dissolve pepsin. Cubes 
of albumen (,4; of an inch) were now placed in the three 
fluids in watch-glasses, some of which were kept for several 
days at about 90° Fahr. (82°-2 Cent.), and others at the 
temperature of my room; but none of the cubes were 
* Sachs remarks (‘Traité de Bot.? or by chemical agents, allow all their 
1874, p. 774), that cells which are colouring matter to escape into the 
killed by freezing, by too great heat, surrounding water. 
