Cuar. IX. EFFECTS OF PREVIOUS IMMERSION. 215 
Period of | 
Immersion, Effects produced on the Leaves by their sub- 
of the sequent Immersion for stated periods in a 
Name of the Salts and | Leaves in Solution of one part of phosphate of 
Acids in Solution. Solutions ammonia to 8750 of water, or 1 gr. to 
of one part 20 oz. 
to 437 of 
water. 
Aluminium nitrate .| 24 hrs. | After 25 hrs.slight and doubtful effect. 
Lead chloride . .| 23 hrs. | After 24 hrs. two leaves somewhat 
inflected, the third very little; and 
thus remained. 
manganese chloride | 22 hrs. | After 48 hrs. not the least inflection. 
Lactic acid . . .| 48 hrs. | After 24 hrs. a trace of inflection in 
a few tentacles, the glands of 
which had not been killed by the 
acid. 
Tannic acid. . .| 24 hrs. | After 24 hrs. no inflection. 
Tartaric acid . .| 24 brs. - Do. do 
Citric acid . . .| 24 hrs. | After 50 m. tentacles decidedly in- 
flected, and after 5 hrs. strongly 
inflected ; so remained for the next 
24 hrs. 
Formic acid. . .| 22 hrs. | Not observed until 24 hrs. had elapsed; 
tentacles considerably inflected, and 
protoplasm aggregated. 
In a large majority of these twenty cases, a varying degree of 
inflection was slowly caused by the phosphate. In four cases, 
however, the inflection was rapid, occurring in less than half an 
hour or at most in 50m. 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 phos- 
phate 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 been previously immersed 
in these three solutions. The majority of the other solutions 
behaved to a certain extent like water, for the phosphate pro- 
duced, after a considerable interval of time, only a slight effect. 
On the other hand, the leaves which had been immersed 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 absorbed from these 
five weak solutions, and yet, owing to the presence of the salts, 
lid not prevent the subsequent action of the phosphate? Or 
15 
