48 DROSERA ROTUNDIFOLIA. Chap. Ill 



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 sj^heres, 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 di'awn 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 

 liere it. will be enough to say that with a sensitive leaf the 

 aUsorption by a gland of ystVoo of ^ S^^^^ ('000482 mgr.) is 

 enough to cause in the course of one hour well-marked aggrega- 

 tion in the cells immediately beneath the gland. 



The Effects of certain otJier Salts and Fluids. — Two leaves were 

 placed in a solution of one part of acetate of ammonia to about 



