Cuar. VIII.) THE EFFECTS OF ACIDS. 159 
placed in water, and after two days partially re-expanded. Hence this 
acid is not poisonous. 
Oxalic Acid.—Three leaves were immersed in ninety minims of a 
solution of 1 gr. to 437 of water; after 2 hrs. 10 m. there was much 
inflection ; glands pale; the surrounding fluid of a dark pink colour ; 
after 8 hrs. excessive inflection. The leaves were then placed in water; 
after about 16 hrs. the tentacles were of a very dark red colour, like 
those of the leaves in acetic acid. Alter 24 additional hours, the three 
leaves were dead and their glands colourless. 
Benzoic Acid.—Five leaves were immersed, each in thirty minims 
of a solution of 1 gr. to 437 0f water. This solution was so weak that 
it only just tasted acid, yet, as we shall see, was highly poisonous to 
Drosera. After 52 m. the submarginal tentacles were somewhat 
inflected, and all the glands very pale-coloured; the surrounding fluid 
was coloured pink. On one occasion the fluid became pink in the 
course of only 12 m. and the glands as white as if the leaf had been 
dipped in boiling water. After 4 hrs. much inflection; but none of 
the tentacles were closely inflected, owing, as I believe, to their having 
been paralysed before they had time to complete their movement. An 
extraordinary quantity of mucus was secreted. Some of the leaves 
were left in the solution; others, after animmersion of 6 hrs, 30 m., 
were placed in water. Next morning both lots were quite dead; the 
leaves in the solution being flaccid, those in the water (now coloured 
yellow) of a pale brown tint, and their glands white. 
Succinic Acid.—Three leaves were immersed in ninety minims of 
a solution of one gr. to 487 of water; after 4 hrs. 15 m. considerable, 
and after 23 hrs. great, inflection; many of the glands pale; fluid 
coloured pink. The leaves were then washed and placed in water; after 
two days there was some re-expansion, but many of the glands were 
still white. his acid is not nearly so poisonous as oxalic or benzcic. 
Uric Acid.—Three leaves were immersed in 180 minims of a solution 
of 1 gr. to 875 of warm water, but all the acid was not dissolved ; so 
that each received nearly p; of a grain. After 25 m. there was some 
slight inflection; but this never increased; after 9 hrs. the glands 
were not discoloured, nor was the solution coloured pink ; nevertheless, 
much mucus was secreted. ‘The leaves were then placed in water, and 
by next morning fully re-expanded. I doubt whether this acid really 
causes inflection, for the slight movement which at first occurred 
may have been due to the presence of a trace of albuminous matter. 
But it produces some effect, as shown by the secretion of so much 
mucus. 
Hippuric Acid—Four leaves were immersed in 120 minims of a 
solution of 1 gr. to 437 of water. After 2 hrs. the fluid was coloured 
pink; glands palc, but no inflection. After 6 hrs. some inflection ; 
after 9 hrs. all four leaves greatly inflected; much mucus secreted; all 
the glands very pale. The leaves were then ielt in water for two days; 
they remained closely inflected, with their glands colourless, and I do. 
not doubt were killed. 
