146 DROSERA ROTUNDIFOLIA. ' Chap. VII. 



and another leaf in the same quantity of a solution of one part 

 to 3062 ; in the former case aggrepjation 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 -2^ 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 those 

 were placed in a drachm (3 ' 549 ml.) 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 alter- 

 nately 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 trans- 

 lucent and red. The four leaves which had been immersed in 

 the solution, besides being inflected, presented a widely difl"erent 

 appearance ; for the contents of the cells of every single tentacle 

 on all four leaves were conspicuously aggregated ; the spheres 

 and elongated masses of protoplasm 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 

 fi)ur 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 

 ■^^28 of a grain (-001009 mg.) of the salt; and this quantity 

 sufficed to induce within a short time conspicuous aggregation 

 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 9^0 of a grain ( -0675 mg.). In 40 m. the glands 

 appeared rather darker; and in 1 hr, from four to six spheres 

 of i^rotoplasm were formed in the cells beneath the glands of 

 all the tentacles. I did not count the tentacles, but we may 



