326 ALDROVANDA VESICULOSA. Cuar. XIV 
already soluble animal matter. The included water 
would thus be pressed out, and the secretion conse- 
quently not be too much diluted to act. With respect 
to the quadrifid processes on the outer parts of the 
lobes, I was not able to decide whether they had been 
acted on by the. infusion; for the lining of proto- 
plasm was somewhat shrunk before they were im- 
mersed. Many of the points on the infolded rims 
also had their lining of protoplasm similarly shrunk, 
and contained spherical granules of hyaline matter. 
A solution of urea was next employed. This sub- 
stance was chosen partly because it is absorbed by the 
quadrifid processes and more especially by the glands 
of Utricularia—a plant which, as we shall hereafter see, 
feeds on decayed animal matter. As urea is one of the 
last products of the chemical changes going on in the 
living body, it seems fitted to represent the early stages 
of the decay of the dead body. I was also led to try 
urea from a curious little fact mentioned by Prof. 
Cohn, namely that when rather large crustaceans are 
caught between the closing lobes, they are pressed so 
hard whilst making their escape that they often void 
their sausage-shaped masses of excrement, which were 
found within most of the leaves. These masses, no 
doubt, contain urea. They would be left either on 
the broad outer surfaces of the lobes where the quad- 
rifids are situated, or within the closed concavity. In 
the latter case, water charged with excrementitious 
and decaying matter would be slowly forced outwards, 
and would bathe the quadrifids, if I am right in 
believing that the concave lobes contract after a time 
like those of Dionza. Foul water would also be apt 
to ooze out at all times, especially when bubbles of air 
were generated within the concavity. 
A leaf was cut open and examined, and the outer 
