96 DROSERA ROTUNDIFOLIA. CHAP. VI 



process of digestion now commenced, 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. Two cubes of albumen (^ of an inch, or 

 035 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. This 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 analo- 

 gous 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 in- 

 flected. 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 dis- 



* Sachs remarks (' Traite de agents, allow all their colouring 



Dot.' 1874, p. 774), that cells matter to escape into the sat* 



which are killed by freezing, by rounding water, 

 too great bent, or by chemical 



