158 DROSERA ROTUNDIFOLIA. [Chap. VIIL 



any motor impulse to the outer tentacles; though these, when 

 their own glands al)8orb the acid, are strongly actcii on. 



Lactic Acid. Three leaves were iuunersed in ninety minims of 

 one part to 437 of water. After 48 m. there was no inlloction, but 

 the surrounding fluid was coloured pink; after 8 hrs. 30 m. one 

 leaf alone was a little intlooted, and almust all the glands on all 

 thi-ce leaves were of a very pale c-olour. The leaves were then 

 wa.shed and placed in a solution (I gr. to 20 oz.) of phosphate of 

 ammonia; after about IC hrs. there was only a trace of intlectioo. 

 They were left in the phosphate for 48 hrs., and remained in the 

 same state, with almost all their glands discoloured. The proto- 

 plasm within the cells was not aggregated, except in a very few ten- 

 tacles, the glands of which were not much discoloured. I believe, 

 therefore, that almost all the glands and tentacles had been killed 

 by the acid so suddenly that hardly any inllcction was caused. 

 Four leaves were next immersed in 120 minims of a weaker solu- 

 tion, of one part to 875 of water; after 2 hrs. 30 m. the sur- 

 rounding lluid was quite pink; the glands were pale, but there 

 was no inflection ; after 7 hrs. 30 m. two of the leaves showed some 

 inflection, and the glands were almost white; after 21 hrs. two of 

 the leaves were considerably inflected, and a third slightly; most 

 of the glands were white, the others dark red. After 45 hrs. one 

 leaf had almost every tentacle inflected; a second a large number; 

 the third and fourth very few; almost all the glands were white, 

 excepting those on the discs of two of the leaves, and many of 

 these were very dark red. The leaves appeared dead. Hence lactic 

 acid acts in a very peculiar manner, causing inflection at an ex- 

 traordinarily slow rate, and being highly poisonous. Immersion in 

 even weaker solutions, viz. of one part to 1312 and 1750 of water, 

 apparently killed the leaves (the tentacles after a time being 

 bowed backwards), and rendered the glands white, but caused no 

 inflection. 



Oallic, Tannic, Tartaric, and Citric Acidg. One part to 437 of 

 water. Three or four leaves were immersed, each in 30 minims of 

 these four solutions, so that each leaf received -j'^ of a grain, or 

 4.048 mg. No inflection was caused in 24 hrs., and the loaves did 

 not appear at all injured. Those which had*been in the tannic and 

 tartaric acids were placed in a solution (1 gr. to 20 oz.) of phos- 

 phate of ammonia, but no inflection ensued in 24 hrs. On the 

 other hand, the four leaves which had been in the citric acid, when 

 treatetl with the phosphate, became decidedly inflected in 50 m., 

 and strongly inflected after 5 hrs., and so remained for the next 

 24 hrs. 



Malic Acid. Three leaves were immerse<l in ninety minims of a 

 solution of one part to 437 of water; no infle<-tion was caused in 

 8 hrs. 20 m., but after 24 hrs. two of them were considerably, and 

 the third slightly, inflected more so than could be accounted for 

 by the action of water. No great amount of mucus was secreted. 

 They were then placed in water, and after two days partially re- 

 expande<l. Hence this acid is not poisonotis. 



Oxalic Acid. Three leaves were immersed in ninety minims ol 



