B34 DROSOPHYLLUM LUSITANICUM. Cuap. XV 
and indeed the two sets almost graduate into one 
another. But the sessile glands differ in one im- 
portant respect, for they never secrete spontaneously, 
as far as I have seen, though I have examined 
them under a high power on a hot day, whilst 
the glands on pedicels were secreting copiously. 
Nevertheless, if little bits of damp albumen or fibrin 
are placed on these sessile glands, they begin after a 
time to secrete, in the same manner as do the glands 
of Dionza when similarly treated. When they were 
merely rubbed with a bit of raw meat, I believe that 
they likewise secreted. Both the sessile glands and 
the taller ones on pedicels have the power of rapidly 
absorbing nitrogenous matter. 
The secretion from the taller glands differs in a 
remarkable manner from that of Drosera, in being acid 
before the glands have been in any way excited; and 
judging from the changed colour of litmus paper, more 
strongly acid than that of Drosera. This fact was 
observed repeatedly ; on one occasion I chose a young 
leaf, which was not secreting freely, and had never 
caught an insect, yet the secretion on all the glands 
coloured litmus paper of a bright red. From the 
quickness with which the glands are able to obtain 
animal matter from such substances as well-washed 
fibrin and cartilage, I suspect that a small quantity of 
the proper ferment must be present in the secretion 
before the glands are excited, so that a little animal 
matter is quickly dissolved. 
Owing to the nature of the secretion or to the shape 
of the glands, the drops are removed from them with 
singular facility. It is even somewhat difficult, by 
the aid of a finely pointed polished needle, slightly 
damped with water, to place a minute particle of any 
kind on one of the drops; for on withdrawing the 
