CHAP. 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 

 22 



