Cuar, IL]  INFLECTION INDIRECTLY CAUSED. 21 
particles from the two latter leaves, and put them on recently 
killed flies. These were fairly well embraced in 73 hrs. and 
thoroughly after 20} hrs.; the tentacles remaining inflected 
for many subsequent days. On the other hand, the one leaf 
which had in the course of 19 hrs. embraced the bit of cinder 
moderately well, and to which no fly was given, after an addi- 
tional 33 hrs. (7.e. in 52 hrs. from the time when the cinder was 
put on) was completely re-expanded and ready to act again. 
From these and numerous other experiments not worth 
giving, it is certain that inorganic substances, or such organic 
substances as are not attacked by the secretion, act much less 
quickly and efficiently than organic substances yielding 
soluble matter which is absorbed. Moreover, I have met 
with very few exceptions to the rule, and these exceptions 
‘apparently depended on the leaf having been tvo recently in 
action, that the tentacles remain clasped for a much longer 
time over organic bodies of the nature just specified than 
over those which are not acted on by the secretion, or 
over inorganic objects.* 
* Owing to the extraordinary be- 
lief held by M. Ziegler (‘Comptes 
rendus,’ May 1872, p. 122), that 
albuminous substances, if held for a 
moment between the fingers, acquire 
the property of making the tentacles 
of Drosera contract, whereas, if not 
thus held, they have no such power, 
I tried some experiments with great 
care, but the results did not confirm 
this belief. Red-hot cinders were 
taken out of the fire, and bits of 
glass, cotton-thread, blotting paper 
and thin slices of cork were immersed 
in boiling water; and particles were 
then placed (every instrument with 
which they were touched having been 
previously immersed in boiling water) 
on the glands of several leaves, and 
they acted in exactly the same 
manner as other particles, which had 
been purposely handled for some 
time. Bits of a boiled egg, cut with 
a knife which had been washed in 
boiling water, also acted like any 
other animal substance. I breathed 
on some leaves for above a minute, 
and repeated the act two or three 
times, with my mouth close to them, 
but this produced no effect. I may 
here add, as showing that the leaves 
are not acted on by the odour of 
nitrogenous substances, that pieces of 
raw meat stuck on needles were fixed 
as close as possible, without actual 
contact, to several leaves, but pro- 
duced no effect whatever. On the 
other hand, as we shall hereafter see, 
the vapours of certain volatile sub- 
stances and fluids, such as of carbonate 
of ammonia, chloroform, certain es- 
sential oils, &c., cause inflection. M. 
Ziegler makes still more extra- 
ordinary statements with respect to 
the power of animal substances, 
which have been left close to, but 
not in contact with, sulphate of 
quinine. The action of salts of 
quinine will be described in.a future 
chapter. Since the appearance of 
the paper above referred to, M. 
Ziegler has published a book on the 
same subject, entitled, ‘Atonicité et 
Zoicité, 1874. 
