274 DROSERA ROTUNDIFOLIA. Cuar. XI. 
In the ninth chapter the effects of the absorption of 
various alkaloids and certain other substances were 
described. Although some of these are poisonous, yet 
as several, which act powerfully on the nervous system 
of animals, produce no effect on Drosera, we may infer 
that the extreme sensibility of the glands, and their 
power of transmitting an influence to other parts of 
the leaf, causing movement, or modified secretion, or 
aggregation, does not depend on the presence of a 
diffused element, allied to nerve-tissue. One of the 
most remarkable facts is that long immersion in the 
poison of the cobra-snake does not in the least 
check, but rather stimulates, the spontaneous move- 
ments of the protoplasm in the cells of the tentacles. 
Solutions of various salts and acids behave very dif- 
ferently in delaying or in quite arresting the sub- 
sequent action of a solution of phosphate of ammonia. 
Camphor dissolved in water acts as a stimulant, as 
do small doses of certain essential oils, for they cause 
rapid and strong inflection. Alcohol is not a stimu- 
lant. The vapours of camphor, alcohol, chloroform, 
sulphuric and nitric ether, are poisonous in moderately 
large doses, but in small doses serve as narcotics or 
anesthetics, greatly delaying the subsequent action 
of meat. But some of these vapours also act as stimu- 
lants, exciting rapid, almost spasmodic movements in 
the tentacles. Carbonic acid is likewise a narcotic, 
and retards the aggregation of the protoplasm when 
carbonate of ammonia is subsequently given. The first 
access of air to plants which have been immersed in 
this gas sometimes acts as a stimulant and induces 
movement. But, as before remarked, a special pharma- 
copeeia would be necessary to describe the diversified 
effects of various substances on the leaves of Drosera. 
In the tenth chapter it was shown that the sensitive- 
