Cuar. VIIL] THE EFFECTS OF ACIDS. 157 
20 hrs., most of the glands were very pale, but some few were almost 
black. No mucus had been secreted, and the surrounding fluid was 
only just perceptibly tinted of a pale pink. After 46 hrs. the leaves 
became slightly flaccid and were evidently killed, as was alterwards 
proved to be the case by keeping them in water. The protoplasm in 
the closely inflected tentacles was not in the least aggregated, but 
towards their bases it was collected in little brownish masses at the 
bottoms of the cells. This protoplasm was dead, for, on leaving the 
leaf in a solution of carbonate of ammonia, no aggregation ensued. 
Propionic acid is highly poisonous to Drosera, like its ally acetic acid, 
but induces inflection at a much slower rate. 
Oleic Acid (given me by Prof. Frankland).—Three leaves were 
immersed in this acid; some inflection was almost immediately 
caused, which increased slightly, but then ceased, and the leaves 
seemed killed. Next morning they were rather shrivelled, and many 
of the glands had fallen off the tentacles. Drops of this acid were 
placed on the discs of four leaves; in 40 m. all the tentacles were 
greatly inflected, excepting the extreme marginal ones; and many of 
these after 3 hrs. became inflected. I was led to try this acid from 
supposing that it was present (which does not seem to be the case)* 
in olive oil, the action of which is anomalous. Thus drops of this oil 
placed on the disc do not cause the outer tentacles to be inflected ; yet, 
when minute drops were added to the secretion surrounding the glands 
of the outer tentacles, these were occasionally, but by no means always, 
inflected. Two leaves were also immersed in this oil, and there was 
no inflection for about 12 hrs.; but after 23 hrs. almost all the tentacles 
were inflected. Three leaves were likewise immersed in unboiled 
linseed oil, and soon became somewhat, and in 3 hrs. greatly inflected. 
After 1 hr. the secretion round the glands was coloured pink. I infer 
from this latter fact that the power of linseed oil to cause inflection 
cannot be attributed to the albumin which it is said to contain. 
Carbolic Acid.—\wo leaves were immersed in sixty minims of a 
solution of 1 gr. to 437 of water; in 7 hrs. one was slightly, and in 24 
hrs. both were closely, inflected, with a surprising amount of mucus 
secreted. These leaves were washed and left for two days in water; 
they remained inflected; most of their glands became pale, and they 
seemed dead. This acid is poisonous, but does not act nearly so 
apidly or powerfully as might have been expected from its known de- 
structive 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, 
* See articles on Glycerine and Oleic Acid in Watts’ ‘ Dict. of Chemistry.’ 
