Onap. XIV. ALDROVANDA VESICULOSA. 327 
cells of the glands were found to contain only limpid 
fluid. Some of the quadrifids included a few spherical 
granules, but several were transparent and empty, and 
their positions were marked. This leaf was now im- 
mersed in a little solution of one part of urea to 146 
of water, or three grains to the ounce. After 3 hrs. 
40 m. there was no change either in the glands or 
quadrifids; nor was there any certain change in the 
glands after 24 hrs.; so that, as far as one trial goes, 
urea does not act on them in the same manner as 
an infusion of raw meat. It was different with the 
quadrifids; for the lining of protoplasm, instead of 
presenting a uniform texture, was now slightly shrunk, 
and exhibited in-many places minute, thickened, irre- 
gular, yellowish specks and ridges, exactly like those 
which appear within the quadrifids of Utricularia 
when treated with this same solution. Moreover, several 
of the quadrifids, which were before empty, now con- 
tained moderately sized or very small, more or less 
aggregated, globules of yellowish matter, as likewise 
occurs under the same circumstances with Utricularia. 
Some of the points on the infolded margins of the 
lobes were similarly affected ; for their lining of proto- 
plasm was a little shrunk and included yellowish 
specks ; and those which were before empty now con 
tained small spheres and irregular masses of hyaline 
matter, more or less aggregated; so that both the 
points on the margins and the quadrifids had absorbed 
matter from the solution in the course of 24 hrs.; but 
to this subject I shall recur. In another rather old 
leaf, to which nothing had been given, but which had 
been kept in foul water, some of the quadrifids con- 
tained aggregated translucent globules. These were 
not. acted on by a solution of one part of carbonate 
of ammonia to 218 of water; and this negative result 
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