18 DROSERA ROTUNDIFOLIA. Cuar. IT} 
ammonia, the fluid within the cells of the tentacles often aggre- 
gates exteriorly into coherent viscid matter, forming a kind of 
bag. Small spheres sometimes appear within this bag, and the 
whole generally soon divides into two or more spheres, which 
repeatedly coalesce and redivide. After a longer or shorter 
time the granules in the colourless layer of protoplasm, which 
flows round the walls, are drawn to and unite with the larger 
spheres, or form small independent spheres ; these latter being of 
a much paler colour, and more brittle than the first aggregated 
masses. After the granules of protoplasm have been thus 
attracted, the layer of flowing protoplasm can no longer be dis- 
tinguished, though a current of limpid fluid still flows round 
the walls. 
If a leaf is immersed in a very strong, almost concentrated, 
solution of carbonate of ammonia, the glands are instantly 
blackened, and they secrete copiously; but no movement of the 
tentacles ensues. ‘Two leaves thus treated became after 1 hr. 
flaccid, and seemed killed; all the cells in their tentacles con- 
tained spheres of protoplasm, but these were small and dis- 
coloured. Two other leaves were placed in a solution not quite 
so strong, and there was well-marked aggregation in 30 m. 
After 24 hrs. the spherical or more commonly oblong masses of 
protoplasm became opaque and granular, instead of being as 
usual translucent; and in the lower cells there were only 
innumerable minute spherical granules. It was evident that 
the strength of the solution had interfered 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 aggregated 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 aggre- 
gation. 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 zs2ig5 Of a grain (*000482 mgr.) is 
enough to cause in the course of one hour well-marked aggrega- 
tion in the cells immediately beneath the gland. 
The Kffects .f certain other Salts and Fluids——Two leaves were 
placed in a solution of one part of acetate of ammonia to about 
