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. 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. 30 m.,
and another in unboiled white of egg for 1 hr. 30 m., were not action
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 [page 52] 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 the
tentacles were not inflected. Glycerine causes in a few minutes
well-pronounced aggregation, commencing as usual within the glands and
then travelling down the tentacles; and this I presume may be
attributed to the strong attraction of this substance for water.
Immersion for several hours in water causes some degree of aggregation.
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