42 DROSERA ROTUNDIFOLIA. (Cua. III. 
granules. It was evident that the strength of the solution had inter- 
fered with the completion of the process, as we shall see likewise 
follows from too great heat. 
All the foregoing observations relate to the exterior tentacles, which 
are of a purple colour; but the green pedicels of the short central 
tentacles are acted on by the carbonate, and by an infusion of raw 
meat, in exactly the same manner, with the sole difference that the 
aggregate masses are of a greenish colour; so that the process is in no 
way dependent on the colour of the fluid within the cells. 
Finally, the most remarkable fact with respect to this salt is the 
extraordinary small amount which suffices to cause aggregation. Full 
details will be given in the seventh chapter, and here it will be enough 
to say that with a sensitive leaf the absorption by a gland of yg3y55 of 
a grain (*000482 mgr.) is enough to cause in the course of one hour 
well-marked aggregation in the cells immediately beneath the gland. 
The Effects of certain other Salts and Fluids.—Two leaves were 
placed in a solution of one part of acetate of ammonia to about 146 of 
water, and were acted on quite as energetically, but perhaps not quite 
so quickly as by the carbonate. After 10 m. the glands were black, and 
in the cells beneath them there were traces of aggregation, which 
after 15 m. was well marked, extending down the tentacles for a length 
equal to that of the glands. After 2 hrs. the contents of almost all 
the cells in all the tentacles were broken up into masses of protoplasm. 
A leaf was immersed in a solution of one part of oxalate of ammonia 
to 146 of water; and after 24 m. some, but not a conspicuous, change 
could be seen within the cells beneath the glands. After 47 m. 
plenty of spherical masses of protoplasm were formed, and these 
extended down the tentacles for about the length of the glands. 
This salt, therefore, does not act so quickly as the carbonate. With 
respect to the citrate of ammonia, a leaf was placed in a little solution 
of the above strength, and there was not eveu a trace of aggregation 
in the cells beneath the glands, until 56 m. had elapsed; but it was 
well marked after 2 hrs. 20 m. On another occasion a leaf was 
placed in a stronger solution, of one part of the citrate to 109 of 
water (4 grs. to 1 oz.), and at the same time another leaf in a 
solution of the carbonate of the same strength. The glands of the 
latter were blackened in less than 2 m., and after 1 hr. 45 m. the 
aggregated masses, which were spherical and very dark-coloured, 
extended down all the tentacles, for between half and two-thirds of 
their lengths; whereas in the leaf immersed in the citrate the glands, 
after 30 m., were of a dark red, and the aggregated masses in the 
cells beneath them pink and elongated. Aiter 1 hr. 45 m. these 
masses extended down for only about one-fifth or one-fourth of the 
length of the tentacles. 
Two leaves were placed, each in ten minims of a solution of one part 
of nitrate of ammonia to 5250 of water (1 gr. to 12 oz.), so that each 
leaf received =4,; of a grain (°1124 mgr.). This quantity caused all 
the tentacles to be inflected, but atter 24 hrs. there was only a trace 
