334 UTRICULARIA NEGLECTA. [Cuar. XVII. 
Four bladders were first tried as a control experiment, in the manner 
just described, in a solution of one part of gum arabic to 218 of water, 
and two bladders in a solution of one part of sugar to 437 of water ; 
and in neither case was any change perceptible in the quadrifids or 
bifids after 21 hrs. Four bladders were then treated in the same 
manner with a solution of one part of nitrate of ammonia to 487 of 
water, and re-examined after 21 hrs. In two cf these the quadrifids 
now appeared full of very finely granular matter, and their protoplasmic 
lining or primordial utricle was a little shrunk. In the third bladder, 
the quadrifids included distinctly visible granules, and the primordial 
utricle was a little shrunk after only 8 hrs. In the fourth bladder the 
primordial utricle in most of the processes was here and there 
thickened into little irregular yellowish specks ; and from the gradations 
which could be traced in this and other cases, these specks appear to give 
rise to the larger free granules contained within some of the processes. 
Other bladders, which, as far as could be judged, had never caught, any 
prey, were punctured and left in the same solution for 17 hrs.; and 
their quadrifids now contained very fine granular matter. 
A bladder was bisected, examined, and irrigated with a solution of 
one part of carbonate of ammonia to 437 of water. After 8 hrs. 30 m. 
the quadrifids contained a good many granules, and the primordial 
utricle was somewhat shrunk; after 23 hrs. the quadrifids and bifids 
contained many spheres of hyaline matter, and in one arm twenty-four 
such spheres of moderate size were counted. Two bisected bladders, 
which had been previously left for 21 hrs. in the solution of gum (one 
part to 218 of water) without being affected, were irrigated with the 
solution of carbonate of ammonia; and both had their quadrifids 
modified in nearly the same manner as just described,—one after only 
9 hrs. and the other after 24 hrs. Two bladders which appeared 
never to have caught any prey were punctured and placed in the 
solution ; the quadrifids of one were examined after 17 hrs., and found 
slightly opaque ; the quadrifids of the other, examined after 45 hrs., had 
their primordial utricles more or less shrunk with thickened yellowish 
specks like those due to the action of nitrate of ammonia. Several un- 
injured bladders were left in the same solution, as well as in a weaker 
solution of one part to 1750 of water, or 1 gr. to 4 oz. ; and after two days 
the quadrifids were more or less opaque, with their contents finely 
granular; but whether the solution had entered by the orifice, or had 
been absorbed from the outside, I know not. 
Two bisected bladders were irrigated with a solution of one part 
of urea to 218 of water; but when this solution was employed, I forgot 
that it had been kept for some days in a warm room, and had there- 
fore probably generated ammonia; anyhow, the quadrifids were 
affected after 21 hrs. as if a solution of carbonate of ammonia had been 
used; for the primordial utricle was thickened in specks, which seemed 
to graduate into separate granules. Three bisected bladders were also 
irrigated with a fresh solution of urea of the same strength; their 
quadrifids after 21 hrs. were much less affected than in the former 
