44 DROSERA ROTUNDIPOLIA. [Chap. III. 



relation to the process of aggregation. A leaf was placed in a solu- 

 tion of one part of chloride of sodium to 218 of water, and after 

 1 hr. the contents of the cells were aggregated into small, irregu- 

 larly globular, brownish masses; these after 2 hrs. were almost dis- 

 integrated and pulpy. It was evident that the protoplasm had 

 been injuriously affected; and soon afterwards some of the cells 

 appeared quite empty. These effects differ altogether from those 

 produced by the several 'salts of ammonia, as well as by various 

 organic fluids, and by inorganic particles placed on the glands. A 

 solution of the same strength of carbonate of soda and carbonate 

 of potash acted in nearly the same manner as the chloride; and 

 here again, after 2 hrs. 30 m., the outer cells of some of the glands 

 had emptied themselves of their brown pulpy contents. We shall 

 see in the eighth chapter that solutions of several salts of soda 

 of half the above strength cause inflection, but do not injure the 

 leaves. Weak solutions of sulphate of quinine, of nicotine, cam- 

 phor, poison of the cobra, &c., soon induce well-marked aggrega- 

 tion; whereas certain other substances (for instance, u solution of 

 curare) have no such tendency. 



Many acids, though much diluted, are poisonous; and though, 

 as will be shown in the eighth chapter, they cause the tentacles to 

 bend, they do not e.xcite true aggregation. Thus leaves were 

 placed in a solution of one part of benzoic acid to 437 of water; 

 and in 15 m. the purple fluid within the cells had shrunk a little 

 from the walls; yet, when carefully examined after 1 hr. 20 m., 

 there was no true aggregation; and after 24 hrs. the leaf was evi- 

 dently dead. Other leaves in iodic acid, diluted to the same d^ree, 

 showed after 2 hrs. 15 m. the same shrunken appearance of the 

 purple fluid within the cells; and these, after 6 hrs. 15 m., were 

 seen under a high power to be filled with excessively minute 

 spheres of dull reddish protoplasm, which by the next morning, 

 after 24 hrs., had almost disappeareil, the leaf being evidently 

 dead. Nor was there any true aggregation in leaves immersed in 

 propionic acid of the same strength; but in this case the proto- 



f>Iasm was collecte<l in irregular masses towards the bases of the 

 ower cells of the tentacles. 



A filtered infusion of raw meat induces strong aggregation, but 

 not very quickly. In one leaf thus immersed there was a little 

 aggregation after 1 br. 20 m., and in another after 1 hr. 50 m. 

 With other leaves a considerably longer time was required: for 

 instance, one immersed for 5 hrs. showed no aggregation, but waa 

 plainly acted on in 5 m., when placed in a few drops of a solution 

 of one part of carbonate of ammonia to 146 of water. Some leaves 

 were left in the infusion for 24 hrs., ond these l)ecame aggregated 

 to a wonderful degree, so that the inflectp<l tentacles presented to 

 the nake<l eye a plainlj' mottled appearnnce. The little masses of 

 purple protoplasm were generally oval or l)eaded, and not nearly so 

 often spherical as in the case of leaves subjected to carbonate of 

 ammonia. They undenvent incessant changes of form; and the 

 current of colourless protoplasm round the walls was conspicuously 

 plain after an immersion of 25 hrs. Raw meat is too powerful a 



