78 DKOSERA ROTUNDIFOLIA. Cuar. V 
30 hrs. Inflection was never thus caused. It is necessary 
to try pure gum arabic, for a friend tried a solution bought 
ready prepared, and this caused the tentacles to bend; but he 
afterwards ascertained that it contained much animal matter, 
probably glue. \ : 
Sugar.—Drops of a solution of white sugar of three strengths 
(the weakest containing one part of sugar to 73 of water) were 
left on fourteen leaves from 32 hrs. to 48 hrs.; but no effect was 
produced. — 
Starch—A mixture about as thick as cream was dropped on 
six leaves and left on them for 30 hrs., no effect being produced. 
I am surprised at this fact, as I believe that the starch of com- 
merce generally contains a trace of gluten, and this nitrogenous 
substance causes inflection, as we shall see in the next chapter. 
Alcohol, Diluted.—One part of alcohol was added to seven of 
water, and the usual drops were placed on the discs of three 
leaves. No inflection ensued in the course of 48 hrs. To ascer- 
tain whether these leaves had been at all injured, bits of meat 
were placed on them, and after 24 hrs. they were closely inflected. 
T also put drops of sherry-wine on three other leaves; no inflec- 
tion was caused, though two of them seemed somewhat injured. 
We shall hereafter see that cut-off leaves immersed in diluted 
alcohol of the above strength do not become inflected. 
Olive Oil.—Drops were placed on the discs of eleven leaves, and 
no effect was produced in from 24 hrs, to 48 hrs. Four of these 
leaves were then tested by bits of meat on their discs, and three 
of them were found after 24 hrs, with all their tentacles and 
blades closely inflected, whilst the fourth had only a few ten- 
tacles inflected. It will, however, be shown in a future place, 
that cut-off leaves immersed in olive oil are powerfully affected. 
Infusion and Decoction of Tea.—Drops of a strong infusion and 
decoction, as well as of a rather weak decoction, of tea were 
placed on ten leaves, none of which became inflected. I after- 
wards tested three of them by adding bits of meat to the drops 
which still remained on their discs, and when I examined them 
after 24 hrs. they were closely inflected. The chemical principle 
of tea, namely theine, was subsequently tried and produced no 
effect. The albuminous matter which the leaves must originally 
have contuined, no doubt, had been rendered insoluble by their 
having been completely dried. 
We thus see that, excluding the experiments with 
water, sixty-one leaves were tried with drops of the 
