1918] 
BONNS—ETHERIZATION AND ENZYME ACTIVITY 239 
there was no difference between reactions in light and 
darkness. 
The experiments of Hempel ('11) indieated that small 
ether dosages of short duration accelerate carbon dioxide pro- 
duction in Pisum seedlings, especially at low temperatures, 
while large doses proportionately retard such action; the 
after-effect of narcosis was a retardation irrespective of 
the concentration used. Thoday (713) investigated the quan- 
titative relation of carbon dioxide evolution and oxygen ab- 
sorption in relation to chloroform doses, using a modified 
form of Bonnier and Mangin's eudiometrie apparatus. He 
believes that the increased respiratory activity produced by 
different agents is not necessarily of the same nature in each 
case and that a substance so chemically inactive as chloro- 
form may have a relatively simple physical effect. Fresh and 
starved leaves of cherry laurel (Helianthus tuberosus) and 
Tropaeolum majus were used. In cherry laurel a weak 
dosage showed a stimulation in production of both gases to 
similar degrees. With strong dosage disorganization was ef- 
fected, accompanied by a rapid inrush of oxygen, diminished 
evolution of carbon dioxide, and browning of tissues. With 
Helianthus similar results were obtained, but chloroform pen- 
etrated more rapidly. Tropaeolum appeared to be inter- 
mediate between the other leaves in susceptibility. In many, 
but not all, cases a relatively greater and more augmented 
respiratory activity occurred in anaesthetized starved leaves, 
as compared with the controls. In general this work con- 
firmed that of Miss Irving. 
Von Когдву (714) studied the effect of chloroform solutions 
on Elodea under controlled conditions of temperature, light, 
and carbon dioxide content of water, using the bubble 
method. He found a range of aqueous solutions which in- 
hibited chlorophyll assimilation; the average concentration 
of such solutions was .074 per cent. At such concentration 
the action was reversible, the usual plant activity being re- 
sumed with a return to normal conditions. The chloroform 
concentration noted was the same as that with which Loeb 
and Wasteneys obtained their results. 
