The glands apparently absorb more quickly than do the quadrifid and bifid processes; and on the view above maintained, namely that they absorb matter from putrid water occasionally emitted from the bladders, they ought to act more quickly than the processes; as these latter remain in permanent contact with captured and decaying animals.

Finally, the conclusion to which we are led by the foregoing experiments and observations is that the bladders have no power of digesting animal matter, though it appears that the quadrifids are somewhat affected by a fresh infusion of raw meat.  It is certain that the processes within the bladders, and the glands outside, absorb matter from salts of [page 424] ammonia, from a putrid infusion of raw meat, and from urea.  The glands apparently are acted on more strongly by a solution of urea, and less strongly by an infusion of raw meat, than are the processes.  The case of urea is particularly interesting, because we have seen that it produces no effect on Drosera, the leaves of which are adapted to digest fresh animal matter.  But the most important fact of all is, that in the present and following species the quadrifid and bifid processes of bladders containing decayed animals generally include little masses of spontaneously moving protoplasm; whilst such masses are never seen in perfectly clean bladders.

Development of the Bladders.—­My son and I spent much time over this subject with small success.  Our observations apply to the present species and to Utricularia vulgaris, but were made chiefly on the latter, as the bladders are twice as large as those of Utricularia neglecta.  In the early part of autumn the stems terminate in large buds, which fall off and lie dormant during the winter at the bottom.  The young leaves forming these buds bear bladders in various stages of early development.  When the bladders of Utricularia vulgaris are about 1/100 inch (.254 mm.) in diameter (or 1/200 in the case of Utricularia neglecta), they are circular in outline, with a narrow, almost closed, transverse orifice, leading into a hollow filled with water; but the bladders are hollow when much under 1/100 of an inch in diameter.  The orifices face inwards or towards the axis of the plant.  At this early age the bladders are flattened in the plane in which the orifice lies, and therefore at right angles to that of the mature bladders.  They are covered exteriorly with papillae of different sizes, many of which have an elliptical outline.  A bundle of vessels, formed of [page 425] simple elongated cells, runs up the short footstalk, and divides at the base of the bladder.  One branch extends up the middle of the dorsal surface, and the other up the middle of the ventral surface.  In full-grown bladders the ventral bundle divides close beneath the collar, and the two branches run on each side to near where the corners of the valve unite with the collar; but these branches could not be seen in very young bladders.