CHAP. III. THE PROCESS OF AGGREGATION. 51 



which by the next morning, after 24 hrs., had almost dis- 

 appeared, 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 protoplasm was collected in 

 irregular masses towards the bases of the lower cells of the 

 tentacles. 



A filtered infusion of raw meat induces strong aggregation, 

 but not very quickly. In one leaf thus immersed there was n 

 little aggregation after 1 hr. 20 m., and in another after 1 hr. 

 50 m. With other leaves a considerably longer time was re- 

 quired : for instance, one immersed for 5 hrs. showed no aggre- 

 gation, but was 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., 

 and these became aggregated to a wonderful degree, so that 

 the inflected tentacles presented to the naked eye a plainly 

 mottled appearance. The little masses of purple protoplasm 

 were generally oval or beaded, and not nearly so often spherical 

 as in the case of leaves subjected to carbonate of ammonia. 

 They underwent incessant changes of form ; and the current of 

 colourless protoplasm round the walls was conspicuously plain 

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

 stimulant, and even small bits generally injure, and sometimes 

 kill, the leaves to which they are given : the aggregated masses 

 of protoplasm become dingy or almost colourless, and present 

 in unusual granular appearance, as is likewise the case with 

 leaves which have been immersed in a very strong solution of 

 carbonate of ammonia. A leaf placed in milk had the contents 

 of its cells somewhat aggregated in 1 hr. Two other leaves, 

 one immersed in human saliva for 2 hrs. 30 m., and another 

 in unboiled white of egg for 1 hr. 30 m., were not acted on in 

 this manner; though they undoubtedly would have been so, 

 had more time been allowed. These same two leaves, on being 

 afterwards placed in a solution of carbonate of ammonia (3 grs. 

 to 1 oz.), had their cells aggregated, the one in 10 m. and the 

 other in 5 m. 



Several leaves were left for 4 hrs. 30 m. in a solution of one 

 part of white sugar to 146 of water, and no aggregation ensued 

 on being placed in a solution of this same strength of carbonate 

 of ammonia, they were acted on in 5 m. ; as was likewise a leaf 

 which had been left for 1 hr. 45 m. in a moderately thick solu- 

 tion of gum arabic. Several other leaves were immersed for 

 some hours in denser solutions of sugar, gum, and starch, and 

 they had the contents of their cells greatly aggregated. This 



