8 DROSERA ROTUNDIFOLIA. [Cuar. I. 
of the tentacles, on which the papilla were seated, now likewise 
contained aggregated masses of protoplasm. We may therefore 
conclude that, when a leaf has closely clasped a captured insect in the 
manner immediately to be described, the papilla, which project from 
the upper surface of the leaf and of the tentacles, probably absorb some 
of the animal matter dissolved in the secretion; but this cannot 
be the case with the papillæ on the backs of the leaves or on the 
petioles. 
Preliminary Sketch of the Action of the Several Parts, and of the 
Manner in which Insects are Captured. 
If a small organic or inorganic object be placed on the 
glands in the centre of a leaf, these transmit a motor impulse 
to the marginal tentacles. The nearer ones are first affected 
and slowly bend towards the centre, and then those farther 
off, until at last all become closely inflected over the object. 
This takes place in from one hour to four or five or more hours. 
The difference in the time required depends on many circum- 
stances ; namely, on the size of the object and on its nature, 
that is, whether it contains soluble matter of the proper 
kind; on the vigour and age of the leaf; whether it has 
lately been in action; and, according to Nitschke,* on the 
temperature of the day, as likewise seemed to me to be the 
case. A living insect is a more efficient object than a dead 
one, as in struggling it presses against the glands of many 
tentacles. An insect, such as a fly, with thin integuments, 
through which animal matter in solution can readily pass 
into the surrounding dense secretion, is more efficient in 
causing prolonged inflection than an insect with a thick coat, 
such as a beetle. The inflection of the tentacles takes place 
indifferently in the light and darkness ; and the plant is not 
subject to any nocturnal movement of so-called sleep. 
If the glands on the disc are repeatedly touched or brushed, 
although no object is left on them, the marginal tentacles 
curve inwards. So again, if drops of various fluids, for 
instance of saliva or of a solution of any salt of ammonia, are 
placed on the central glands, the same result quickly follows, 
sometimes in under half an hour. 
The tentacles in the act of inflection sweep through a wide 
space; thus a marginal tentacle, extended in the same plane 
with the blade, moves through an angle of 180°; and I have 
* ‘Bot, Zeitung,’ 1860, p. 246. 
