Chap. VII.] CARBONATE OP AMMONIA. 110 



Ammonia. I have fully described in the third chapter the remark- 

 able effects of moderately strong doses of this salt in causing the 

 aggregation of the protoplasm within the cells of the glands and 

 tentacles; and here my object is merely to show what small doses 

 suffice. A leaf was immersed in twenty minims (1.183 c.c.) of a 

 solution of one part to 1750 of water, and another leaf in the same 

 quantity of a solution of one part to 3062 ; in the former case aggre- 

 gation occurred in 4 m., in the latter in 11 m. A leaf was then 

 immersed in twenty minims of a solution of one part to 4375 of 

 water, so that it received ^hs of a grain (.27 mg.) ; in 5 m. there 

 was a slight change of colour in the glands, and in 15 m. small 

 spheres of protoplasm were formed in the cells beneath the glands 

 of all the tentacles. In these cases there could not be a shadow 

 of a doubt about the action of the solution. 



A solution was then made of one part to 5250 of water, and I 

 experimented on fourteen leaves, but will give only a few of the 

 cases. Eight young leaves were selected and examined with care, 

 and they showed no trace of aggregation. Four of these were 

 placed in a drachm (3.549 c.c.) of distilled water; and four in a 

 similar vessel, with a drachm of the solution. After a time the 

 leaves were examined under a high power, being taken alternately 

 from the solution and the water. The first leaf was taken out of 

 the solution after an immersion of 2 hrs. 40 m., and the last leaf 

 out of the water after 3 hrs. 50 m. ; the examination lasting for 1 

 hr. 40 m. In the four leaves out of the water there was no trace of 

 aggregation except in one specimen, in which a very few extremely 

 minute spheres of protoplasm were present beneath some of the 

 round glands. All the glands were translucent and red. The four 

 leaves which had been immersed in the solution, besides being in- 

 flected, presented a widely different appearance; for the contents 

 of the cells of every single tentacle on all four leaves were con- 

 spicuously aggregated ; the spheres and elongated masses of proto- 

 plasm in many cases extending halfway down the tentacles. All 

 the glands, both those of the central and exterior tentacles-, were 

 opaque and blackened; and this shows that all had absorbed some 

 of the carbonate. These four leaves were of very nearly the same 

 size, and the glands were counted on one and found to be 167. 

 This being the case, and the four leaves having been immersed in 

 a drachm of the solution, each gland could have received on an 

 average only ^^irr o^ ^ grain (.001009 mg.) of the salt: and this 

 quantity sufficed to induce within a short time conspicuous aggre- 

 gation in the cells beneath all the glands. 



A vigorous but rather small red leaf was placed in six minims 

 of the same solution (viz. one part to 5250 of water), so that it 

 received 5^u of a grain (.0675 mg.). In 40 m. the glands appeared 

 rather darker; and in 1 hr. from four to six spheres of protoplasm 

 were forme<l in the cells beneath the glands of all the tentacles. I 

 did not count the tentacles; but we may safely assume that there 

 were at least 140; and if so, each gland could" have received only 

 the TTAnff of a grain, or .00048 mg. 



A weaker solution was then made of one part to 7000 of water, 



