44 DROSERA ROTUNDIFOLIA. [Cuap. IIT. 
the next morning, after 24 hrs., had almost disappeared, 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 a little aggre- 
gation after 1 hr. 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 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 fur 24 hrs., and these became aggregated to a wonderful 
degree, so that the inflected tentacles presented to the naked eyea 
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 under- 
went incessant changes of form; and the current of colourless proto- 
plasm round the walls was conspicuously plain after an immersion of 
25 hrs. Raw 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 an 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. 80 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 solution 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 effect may be attributed to exosmose; for 
the leaves in the syrup became quite flaccid, and those in the gum and 
starch somewhat flaccid, with their tentacles twisted about in the 
most irregular manner, the longer ones like corkscrews. We shall 
hereafter see that solutions of these substances, when placed on the 
discs of leaves, do not incite inflection. Particles of soft sugar were 
added to the secretion round several glands and were soon dissolved, 
causing a great increase of the secretion, no doubt by exosmose; and 
after 24 hrs. the cells showed a certain amount of aggregation, though 
