Cuar. Vi) ZFFECTS OF ORGANIC FLUIDS. 67 
was converted-into a cup. The power of urine does not lie in the 
urea, which, as we shall hereafter see, is inoperative. 
_ Albumen (fresh from a hen’s egg), placed on seven leaves, caused 
the tentacles of six of them to be well inflected. In one case the edge 
of the leaf itself became much curled in after 20 hrs. The one leaf 
which was, unaffected remained so for 26 hrs., and was then treated 
ee drop of milk, and this caused the tentacles to bend inwards in 
12 brs.. in aid : 
Cold Filtered Infusion of Raw Meat.—This was tried only ona 
single leaf, which had most of its outer tentacles and the blade inflected 
in 19 hrs. . During subsequent years I repeatedly used this infusion to 
test leaves which had been experimented on with other substances, and 
_it was found to act most energetically, but as no exact account of these 
trials was kept, they are not here introduced. 
Mucus.—Thick and thin mucus from the bronchial tubes, placed on 
three leaves, caused inflection. A, leaf with thin mucus had its 
-marginal tentacles and blade somewhat curved inwards in 5 hrs, 30 m. 
and greatly so in 20 hrs. The action of, this fluid no doubt is due 
either to the saliva or to some albuminous matter* mingled with it, 
and not, as we shall see in the next chapter, to mucin or the chemical 
principle of mucus. 
Saliva.—Human saliva, when evaporated, yieldst from 1°14 to 
1°19 per cent. of residue; and this yields 0°25 per cent. of ashes, so 
that the proportion of nitrogenous matter which saliva contains must 
be small. Nevertheless, drops placed on the discs of eight leaves acted 
on them all. In one case all the exterior tentacles, excepting nine, 
were inflected in 19 hrs. 830 m.; in another case a few became so in 2 
hrs., and after 7 hrs. 30 m. all those situated near where the drop lay, 
as well as the blade, were acted on, Since making these trials, 1 have 
yaany scores of times just touched the glands with the handle of my 
scalpel wetted with saliva, to ascertain whether a leaf was in an active 
condition; for this was shown in the course. of a few minutes by the 
bending inwards of the tentacles. The edible nest of the Chinese 
swallow is formed of matter secreted by the salivary glands; two 
grains were added to one ounce of distilled water (one part to 218), 
which was boiled for several’ minutes, but did not dissolve the whole. 
The usual-sized drops were placed on three leaves, and these in 1 hr. 
30 m. were well, and in 2 hrs. 15 m. closely, inflected. . 
Isinglass.—Drops of a solution about as thick as milk, and of a still 
thicker solution, were placed on eight leaves, and the tentacles of all 
became inflected. In one case the exterior tentacles were well curved 
in after 6 hrs. 80 m., and the blade of the leaf to a partial extent after 
24hrs. As saliva acted so efficiently, and yet contains so smalla 
proportion of nitrogenous matter, I tried how small a quantity of 
* Mucus from the air-passages is some albumen. : 
said in Marshall, ‘Outlines of Physi- + Miiller’s ‘ Elements of Physiology,’ 
ology, vol ii. 1867, p. 364, to contain Eng. Trans. vel. i. p. 514, , 
: F 
