174 DROSEBA ROTUNDIFOLIA. [Cuap. IX. 



day in the solution, still remained quite unaffected. When, how- 

 ever, some of these leaves, which had been first immersed in water 

 for 24 hrs. and then in the phosphate for 24 hrs., were placed in a 

 solution of carbonate of ammonia (one part to 218 of water), the 

 protoplasm in the cells of the tentacles became in a few hours 

 strongly aggregated, showing that this salt had been absorbed 

 and taken effect. 



A short immersion in water for 20 m. did not retard the subse- 

 quent action of the phosphate, or of splinters of glass placed on 

 the glands; but in two instances an immersion for 50 m. prevented 

 any effect from a solution of camphor. Several leaves which had 

 been left for 20 m. in a solution of one part of white sugar to 218 

 of water were placed in the phosphate solution, the action of 

 which was delaye<l; whereas a mixed solution of sugar and the 

 phosphate did not in the least interfere with the effects of the latter. 

 Three leaves, after being immersed for 20 m. in the sugar solution, 

 were placed in a solution of carbonate of ammonia (one part to 218 

 of water) ; in 2 m. or 3 m. the glands were blackened, and after 

 7 ni. the tentacles were considerably inflected, so that the solution 

 of sugar, though it delayed the action of the phosphate, did not 

 delay that of the carbonate. Immersion in a similar solution of 

 gum arable for 20 m. had no retarding action on the phosphate. 

 Three leaves were left for 20 m. in a mixture of one part of alcohol 

 to seven parts of water, and then placed in the phosphate solution: 

 in 2 hrs. 15 m. there was a trace of inflection in one leaf, and in 

 5 hrs. 30 m. a second was slightly affected; the inflection subse- 

 quently increased, though slowly. Hence diluted alcohol, which, 

 as we shall see, is hardly at all poisonous, plainly retards the sub- 

 sequent action of the phosphate. 



It was shown in the last chapter that leaves which did not be- 

 come inflected by nearly a day's immereion in solutions of various 

 salts and acids behaved very differently from one another when 

 subsequently placed in the phosphate solution. I give on the op- 

 posite page a table summing up the results. 



In a large majority of these twenty cases, a varying degree of 

 inflection was slowly caused by the phosphate. In four cases, how- 

 ever, the inflection was rapid, occurring in less than half an hour 

 or at most in .50 m. In three cases the phosphate did not produce 

 the least effect. Now what are we to infer from these facts? We 

 know from ten trials that immersion in distilled water for 24 hrs. 

 prevents the subsequent action of the phosphate solution. It 

 would therefore appear as if the solutions of chloride of manganese, 

 tannic and tartaric acids, which are not poisonous, acted exactly 

 like water, for the phosphate produced no effect on the leaves 

 which had l)een previously immersed in these three solutions. The 

 majority of the other solutions behaved to a certain extent like 

 water, for the phosphate pro<luced. after a considerable interval of 

 time, only a slight effect. On the other hand, the leaves which 

 had been immersetl in the solutions of the chloride of rubidium and 

 magnesium, of acetate of strontium, nitrate of barium, and citric 

 acid, were quickly acted on by the phosphate. Now, was water 



