158 DROSERA ROTUNDIFOLIA. (Cuar. VIII. 
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 487 of water. After 48 m. there was no inflection, but the 
surrounding fluid was coloured pink; after 8 hrs. 80 m. one leaf alone 
was a little inflected, and almost all the glands on all three lcaves 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 almest all their 
glands disccloured. The protoplasm within the cells was not ag- 
gregated, 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 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, casing inflection at an extraordinarily slow rate, and being 
highly poisonous. Immersion in ‘even weaker solutions, viz. of one 
part to 1812 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 30 minims of these 
four solutions, so that each leaf received J, of a grain, or 4048 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 2+ hrs, 
Malic acid.—Three leaves were immersed in ninety minims of a 
solution of one part to 437 of water; no inflection 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 them 
