Chap. XIV.] ALDROVANDA VESICULOSA. 265 



fluid, spherical masses of a granular substance, showing that 

 matter had been absorbed from the infusion. That these 

 glands secrete a fluid which dissolves or digests animal mat- 

 ter out of the bodies of the creatures which the leaves cap- 

 ture, is also highly probable from the analogy of Diontea. If 

 we may truSt to the same analogy, the concave and inner 

 portions of the two lobes probably close together by a slow 

 movement, as soon as the glands have absorbed a slight 

 amount of 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 protoplasm was somewhat shrunk 

 before they were immersed. Many of the points on the in- 

 folded rims also had their lining of protoplasm similarly 

 shrunk, and contained spherical granules of hyaline matter. 



A solution of urea was next employed. This substance 

 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 men- 

 tioned by Prof. Cohn, namely, that when rather large crus- 

 taceans 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 quadrifids are situated, or 

 within the closed concavity. In the latter case, water 

 charged with excrement itious 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 Dioneea. 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 cells of 

 the glands were found to contain only limpid fluid. Some 



