50 DKOSEKA ROTUNDIFOLIA. CiiAf. 1U 



lowed from an immersion of from 5 m. to 10 m. in an equally 

 strong solution of the carbonate. 



Lastly, a leaf was placed in thirty minims of a solution of 

 one part of phosphate of ammonia to 4.3,750 of water (1 gr. to 

 100 oz.), so that it received j-gVo f a g ra i n ('04079 mgr.); this 

 soon caused the tentacles to be strongly inflected ; and after 

 24 hrs. the contents of the cells were aggregated into oval 

 and irregularly globular masses, with a conspicuous current of 

 protoplasm flowing round the walls. But after so long an 

 interval aggregation would have ensued, whatever had caused 

 inflection. 



Only a few other salts, besides those of ammonia, were tried 

 in relation to the process of aggregation. A leaf was placed in 

 a solution of one part of chloride of sodium to 218 of water, and 

 after 1 hr. the contents of the cells were aggregated into small, 

 irregularly globular, brownish masses ; these after 2 hrs. were 

 almost disintegrated and pulpy. It was evident that the proto- 

 plasm had been injuriously affected ; and soon afterwards some 

 of the cells appeared quite empty. These effects differ alto- 

 gether from those produced by the several salts of ammonia, 

 as well as by various organic fluids, and by inorganic particles 

 placed on the glands. A solution of the same strength of car- 

 bonate of soda and carbonate of potash acted in nearly the same 

 manner as the chloride ; and here again, after 2 hrs. 30 m., the 

 outer cells of some of the glands had emptied themselves of 

 their brown pulpy contents. We shall see in the eighth 

 chapter that solutions of several salts of soda of half the above 

 strength cause inflection, but do not injure the leaves. Weak 

 solutions of sulphate of quinine, of nicotine, camphor, poison of 

 the cobra, &c., soon induce well-marked aggregation ; whereas 

 certain other substances (for instance, a solution of curare) 

 have no such tendency. 



Many acids, though much diluted, are poisonous ; and though, 

 as will be shown in the eighth chapter, they cause the ten- 

 tacles to bend, they do not excite true aggregation. Thus leaves 

 were placed in a solution of one part of benzoic acid to 437 of 

 water; and in 15m. the purple fluid within the cells had shrunk 

 a little from the walls, yet when carefully examined after 1 hr. 

 20 m., there was no true aggregation ; and after 24 hrs. the leaf 

 was evidently dead. Other leaves in iodic acid, diluted to tht, 

 same degree, showed after 2 hrs. 15 m. the same shrunken 

 appearance of the purple fluid within the cells ; and these, 

 after 6 hrs. 15 m., were seen under a high power to be filled 

 with excessively minute spheres of dull reddish protoplasm, 



