92 DROSERA ROTUNDIFOLIA. CHAP. VI. 



I will now give in detail my experiments on the 

 digestive power of the secretion of Drosera, dividing 

 the substances tried into two series, namely those 

 which are digested more or less completely, and those 

 which are not digested. We shall presently see that 

 all these substances are acted on by the gastric juice 

 of the higher animals in the same manner. I beg 

 leave to call attention to the experiments under the 

 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 pre- 

 mise 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 specimens, the central parts were 

 still white and opaque. So that their state differed 

 widely, as we shall see, from that of the cubes sub- 

 jected 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 



