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to the stimulating action of small quantities of fatigue substances, 
which in higher concentrations decrease irritability. On the plant 
side numerous practical uses have been made of the fact that 
many depressant substances when administered in low concentra- 
tion increase rate of growth. Thus ether has been used in 
“forcing” plant growth by those interested in commercial horti- 
culture. 
Other striking effects of narcosis on the side of oxygen con- 
sumption have been recorded in plants when they were treated 
with weak solutions of chloroform and ether. “Tashiro and 
Adams cite observations of Kosinski showing that respiration in 
yeast cells increased in presence of 0.5 per cent ether ; 5 per cent 
reduces respiration one-half while 7 per cent almost stops it” ® 
Rotation in plant cells has been observed within the protoplasm 
during the early stages of ether and chloroform narcosis, and it 
is recorded that the irritability of certain sensitive plants is 
heightened in the presence of traces of 'ether. 
Loeb, Lillie, Torrey, Moore and others have observed striking 
behavior activities induced in various organisms when these were 
treated with the proper concentrations of certain anaesthetics. 
Thus Loeb was able to produce a positive heliotropic response in 
Daphniae when he had subjected it to solutions of alcohol and 
ether.in strengths that vary from a third to a half of those required 
for anaesthesia. Lillie in experiments with the marine annelid 
larvae (Arenicola) found that he could change the behavior from 
a normally positive to a negative heliotropism in various weak 
anaesthetic substances. 
On the other hand and opposite to sensitization, is the phe- 
nomenon of reversible decrease in irritability or responsitiveness, 
which is anaesthesia, and the vital processes that are subject to 
such an arrest are numerous and varied, and may be brought about 
in a number of different ways, i. e., mechanical, thermal, electri- 
cal or chemical. In discussing the theory of anaesthesia, Lillie® 
lists a few of the vital processes so affected as follows : They in- 
clude amoeboid movements ; protoplasmic rotation in plant cells ; 
all processes depending on response to stimulation, like muscular 
contraction and stimulation and conduction in nerve; automatic 
rhythmical activities like the heart beat or the motion of cilia or 
spermatazoa; cell-division; the artificial initiation* of development 
in unfertilized eggs ; various fermentative and oxidative processes ; 
light-production, e. g., by luminous bacteria ; typical metabolic 
processes like the assimilation of carbon dioxide by plants ; growth 
