rapidly or powerfully as might have been expected from its known destructive power on the lowest organisms.  Half-minims of the same solution were placed on the discs of three leaves; after 24 hrs. no inflection of the outer tentacles ensued, and when bits of meat were given them, they became fairly well inflected.  Again half-minims of a stronger solution, of one part to 218 of water, were placed on the discs of three leaves; no inflection of the outer tentacles ensued; bits of meat were then given as before; one leaf alone became well inflected, the discal glands of the other two appearing much injured and dry.  We thus see that the glands of the discs, after absorbing this acid, rarely transmit any motor impulse to the outer tentacles; though these, when their own glands absorb the acid, are strongly acted on.

Lactic Acid.—­Three leaves were immersed in ninety minims of one part to 437 of water.  After 48 m. there was no inflection, but the surrounding fluid was coloured pink; after 8 hrs. 30 m. one leaf alone was a little inflected, and almost all the glands on all three leaves were of a very pale colour.  The leaves were then washed and placed in a solution (1 gr. to 20 oz.) of phosphate of ammonia; after about 16 hrs. there was only a trace of inflection.  They were left in the phosphate for 48 hrs., and remained in the same state, with almost all their glands discoloured.  The protoplasm within the cells was not aggregated, except in a very few tentacles, 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 inflection was caused.  Four leaves were next immersed in 120 minims of a weaker solution, of one part to 875 of water; after 2 hrs. 30 m. the surrounding fluid was quite pink; the glands were pale, but [page 194] 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 extraordinarily 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.

Gallic, Tannic, Tartaric, and Citric Acids.—­One part to 437 of water.  Three or four leaves were immersed, each in thirty minims of these four solutions, so that each leaf received 1/16 of a grain, or 4.048 mg.  No inflection was caused in 24 hrs., and the leaves 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 phosphate of ammonia, but no inflection ensued in 24 hrs.  On the other hand, the four leaves which had been in the citric acid, when treated with the phosphate, became decidedly inflected in 50 m. and strongly inflected after 5 hrs., and so remained for the next 24 hrs.