r)4 DROSERA ROTUNDIFOLIA. Chap. III. 



could be scon filled with purple fluid, without a vestige of 

 aggregated protoplasm ; the whole having been redissolved. A 

 leaf witli aggregated masses, caused by its having been waved 

 for 2 m. in water at the temperature of 125° Fahr., was left in 

 cold water, and after 11 hrs. the protoplasm showed traces 

 of incipient redissolution. When again examined three days 

 after its immersion in the warm water, there was a conspicuous 

 difference, though the protoplasm was still somewhat aggre- 

 gated. Another leaf, with the contents of all the cells strongly 

 aggregated from the action of a weak solution of phosphate of 

 ammonia, was left for between three and four days in a mixture 

 (known to be innocuous) of one drachm of alcohol to eight 

 drachms of water, and when re-examined every trace of aggre- 

 gation had disappeared, the cells being now filled with homo- 

 geneous fluid. 



We have seen that leaves immersed for some hours in dense 

 solutions of sugar, gum, and starch, have the contents of their 

 cells greatly aggregated, and are rendered more or less flaccid, 

 with tlie tentacles irregularly contorted. These leaves, after 

 being left for four days in distilled water, became less flaccid, 

 with tlieir tentacles partially re-expanded, and the aggi'e- 

 gated masses of protoplasm were partially redissolved. A leaf 

 with its tentacles closely clasped over a fly, and with the con- 

 tents of the cells strongly aggregated, was placed in a little 

 sherry wine ; after 2 hrs. several of the tentacles had re- 

 expanded, and the others could by a mere touch be pushed back 

 into their properly expanded positions, and now all traces of 

 aggregation had disappeared, the cells being filled with perfectly 

 liomogeneous pink fluid. The redissolution in these cases may, 

 I presume, be attributed to endosmose. 



On the Proximate Causes of the Process of Aggregation. 



As most of the stimulants which cause the inflection 

 of the tentacles likewise induce aggregation in the 

 contents of their cells, this latter process might be 

 thouglit to be the direct result of inflection ; but this 

 is not the case. If leaves are placed in rather strong 

 solutions of carbonate of ammonia, for instance of 

 three or four, and even sometimes of only two grains 

 to the ounce of water (i.e. one part to 109, or 146, or 



