Chap. III.] THE PROCESS OF AGGREGATION. 43 



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 ni. 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 immei-setl in a 

 solution of one part of oxalate of ammonia to 14G of water; and 

 after 24 ra. some, but not a conspicuous, change could be seen 

 within the cells beneath the glands. After 47 m. plenty of spher- 

 ical masses of protoplasm were formed, and these extended down 

 the tentacles for about the length of the glands. This salt, there- 

 fore, does not act so quickly as the carbonate. With respect to 

 the citrate of ammonia, a leaf was place<i in a little solution of 

 the above strength, and there was not even a trace of aggiegation 

 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. After 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 yj^ of grain (.1124 njgr.). This quantity 

 caused all the tentacles to be inflected, but after 24 hrs. there was 

 only a trace of aggregation. One of these same leaves was then 

 placed in a weak solution of the carbonate, and after 1 hr. 45_ m. 

 the tentacles for half their lengths showed an astonishing degree 

 of aggregation. Two other leaves were then placed in a much 

 stronger solution of one part of the nitrate to 146 of water (3 

 grs. to 1 oz.) ; in one of these there was no marked change after 3 

 hrs. ; but in the other there was a trace of aggregation after 52 m., 

 and this was plainly marked after 1 hr. 22 m., but even after 

 2 hrs. 12 m. there was certainly not more aggregation than would 

 have followed 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 43,750 of water (1 gr. to 100 oz.), 

 so that it received i^TT of a grain (.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, \^-ith a conspicuous current of protoplasm flowing round 

 the walls. But after so long an inter^'al aggregation would have 

 ensued, whatever had caused inflection. 



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



