left for an additional day in the solution, still remained quite unaffected.  When, however, 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 subsequent 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 delayed; 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 m. 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 arabic 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, [page 214] 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 subsequently increased, though slowly.  Hence diluted alcohol, which, as we shall see, is hardly at all poisonous, plainly retards the subsequent action of the phosphate.

It was shown in the last chapter that leaves which did not become inflected by nearly a day’s immersion in solutions of various salts and acids behaved very differently from one another when subsequently placed in the phosphate solution.  I here give a table summing up the results.

Column 1 :  Name of the Salts and Acids in Solution.  Column 2 :  Period of Immersion of the Leaves in Solutions of one part to 437 of water.  Column 3 :  Effects produced on the Leaves by their subsequent Immersion for stated periods in a Solution of one part of phosphate of ammonia to 8750 of water, or 1 gr. to 20 oz.

Rubidium chloride. :  22 hrs. :  After 30 m. strong inflection of the tentacles.

Potassium carbonate :  20 m. :  Scarcely any inflection until 5 hrs. had elapsed.

Calcium acetate. :  24 hrs. :  After 24 hrs. very slight inflection.

Calcium nitrate. :  24 hrs. :  Do. do.

Magnesium acetate. :  22 hrs. :  Some slight inflection, which became well pronounced in 24 hrs.

Magnesium nitrate. :  22 hrs. :  After 4 hrs. 30 m. a fair amount of inflection, which never increased.