300 DIONZA MUSCIPULA. Cupar. XLII, 
well aggregated. Aggregation may be seen to occur 
very: quickly if a piece of a leaf is immersed in 
a weak solution of carbonate of ammonia. Again, 
small cubes of albumen and gelatine were left for 
eight days on a leaf; which was then cut open. The 
whole surface was bathed with acid secretion, and 
every cell in the many glands which were examined 
had its contents aggregated in a beautiful manner 
into dark or pale purple, or colourless globular 
masses of protoplasm. These underwent incessant 
slow changes of forms; sometimes separating from 
one another and then reuniting, exactly as in the 
cells of Drosera. Boiling water makes the contents 
of the gland-cells white and opaque, but not so 
purely white and porcelain-like as in the case of 
Drosera. How living insects, when naturally caught, 
excite the glands to secrete so quickly as they do, I 
know not; but I suppose that the great pressure to 
which they are subjected forces a little excretion 
from either extremity of their bodies, and we have 
seen that an extremely small amount of nitrogenous 
matter is sufficient to excite the glands. 
Before passing on to the subject of digestion, I may 
state that I endeavoured to discover, with no success, 
the functions of the minute octofid processes with 
which the leaves are studded. From facts hereafter to 
be given in the chapters on Aldrovanda and Utricu- 
laria, it seemed probable that they served to absorb 
decayed matter left by the captured insects; but 
their position on the backs of the leaves and on the 
footstalks rendered this almost impossible. Never- 
theless, leaves were immersed in a solution of one part 
of urea to 437 of water, and after 24 hrs. the orange 
layer of protoplasm within the arms of these processes 
did not appear more aggregated than in other speci: 
