CHAP. IX. EFFECTS OF PREVIOUS IMMERSION. 213 



from these facts that a mixture of four drops of glycerine to 

 an ounce of water is not poisonous, and excites very little in- 

 flection; but that pure glycerine is poisonous, and if applied 

 in very minute quantities to the glands of the outer tentacles 

 causes their inflection. 



The Effects of Immersion in Water and in various Solutions tin 

 the subsequent Action of Phosphate and Carbonate of Ammonia. 

 We have seen in the third and seventh chapters that immersion 

 in distilled water causes after a time some degree of aggregation 

 of the protoplasm, and a moderate amount of inflection, espe- 

 cially in the case of plants which have been kept at a rather 

 high temperature. Water does not excite a copious secretion 

 of mucus. We have here to consider the effects of immersion 

 in various fluids on the subsequent action of salts of ammonia 

 and other stimulants. Four leaves which had been left for 

 24 hrs. in water were given bits of meat, but did not clasp them. 

 Ten leaves, after a similar immersion, were left for 24 hrs. in 

 a powerful solution (1 gr. to 20 oz.) of phosphate of ammonia, 

 and only one showed even a trace of inflection. Three of 

 these leaves, on being 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 pro- 

 toplasm 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 sub- 

 sequent action of the phosphate, or of splinters of glass placed 

 on the glands ; but in two instances an immersion for 50 m. pre- 

 vented 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 wator 



