22 DROSERA ROTUNDIFOLIA. Cua. IL 
outer tentacles to bend inwards. But this follows 
much more surely and quickly, if the object contains 
nitrogenous matter which can be dissolved by the 
secretion. On one occasion I observed the follow- 
ing unusual circumstance. Small bits of raw meat 
(which acts more energetically than any other sub- 
stance), of paper, dried moss, and of the quill of a 
pen were placed on several leaves, and they were all 
embraced equally well in about 2 hrs. On other 
occasions the above-named substances, or more com- 
monly particles of glass, coal-cinder (taken from the 
fire), stone, gold-leaf, dried grass, cork, blotting-paper, 
cotton-wool, and hair rolled up into little balls, were 
used, and these substances, though they were some- 
times well embraced, often caused no movement what- 
ever in the outer tentacles, or an extremely slight and 
slow movement. Yet these same leaves were proved to 
be in an active condition, as they were excited to move 
by substances yielding soluble nitrogenous matter, 
such as bits of raw or roast meat, the yolk or white of 
boiled eggs, fragments of insects of all orders, spiders, 
&c. I will give only two instances. Minute flies were 
placed on the discs of several leaves, and on others 
balls of paper, bits of moss and quill of about the same 
size as the flies, and the latter were well embraced 
in a few hours; whereas after 25 hrs. only a very 
few tentacles were inflected over the other objects. 
The bits of paper, moss, and quill were then removed 
from these leaves, and bits of raw meat placed on them ; 
and now all the tentacles were soon energetically 
inflected. x 
Again, particles of coal-cinder (weighing rather more 
than the flies used in the last experiment) were placed 
on the centres of three leaves: after an interval of 
19 hrs. one of the particles was tolerably well embraced; 
