Chap. IX. EFFECTS OF rEEVIOUS IMMERSION. 



215 



Name of the Salts and 

 Atids in Solution. 



Aluminium nitrate . 

 L(nid chloride . 



IMauGranese chloride 

 Lactic acid . 



Tannic acid . 

 Tartaric acid 

 Citric acid . 



Formic acid 



Period of 

 Immersion 



of the 



Leaves in 



Solutions 



of one part 



to 437 of 



water. 



Effects produced on the Leaves by their sub- 

 sequent Immersion for stated periods in a 

 Solution of one part of phosphate of 

 ammonia to 8750 of water, or 1 gr. to 

 20 oz. 



After 25 hrs. slight and doubtful effect. 



After 24 hrs. two leaves somewhat 

 inflected, the third very little ; and 

 thus remained. 



After 48 hrs. not the least inflection. 



After 24 hrs. a trace of inflection in 

 a few tentacles, the glands of 

 which had not been killed by the 

 acid. 



After 24 hrs. no inflection. " 

 Do. do. 



After 50 m. teutacles decidedly in- 

 flected, and after 5 hrs. strongly 

 inflected ; so remained for the next 

 24 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 

 injflection was slowly caused by the phosphate. In fonr cases, 

 however, 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 phos- 

 phate sohition. 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, 

 .did not prevent the subsequent action of the phosphate ? Or 



