326 ALDROVANDA VESICULOSA. Chap. XIV 



already soluble animal matter. Tlie 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 w^ere 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 Dionaea. 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 



