888 MR. A. J. EWART ON ASSIMILATORY INHIBITION. 
same temperature, and then brought to 20° C. and kept under 
continuous observation. f 
Im the first six plants all the leaves remain living and recover. 
In both Lupinus and Phaseolus the foliage leaves, which after a 
day or so at 20° C. are entirely dead, contained at first many 
plasmolysable cells with normal chlorophyll grains. These cells 
show no evolution of oxygen and do not recover, having perma-, 
nently lost the power of assimilation. | 
A prolonged stoppage of assimilation produced as a result of 
moist heat alone can only be brought about when the temperature 
to which the plant is heated approaches dangerously near to its 
critical point (Table I). The plants were heated in darkness 
with a relatively abundant supply of moist air. 
TABLE I. 
1 day at 40? C. 1 day at 45? C. 
Cladonia | Gonidia mostly living. No evolution of O. Dead. 
rangiferina. | In 1h.at 20? C. weak evolution of O, which 
in 3 hours is moderately active. 
Oxalis Most leaves living, few with brownish dead ” 
Acetosella. patches. Both no evolution of O, in 2 hrs. 
moderately active in former, in latter still 
weak after 5 hrs., moderately active in 1 day. 
Dicranum | Plenty of living leaves; chl. grains normal, ” 
scoparium. but protoplasm somewhat attenuated. No 
evolution of O, after 1 day still imperceptible, 
in 2 days weak, and in 5 days active from 
all still living cells. 
Bryum Most leaves living. After 8 hours no evolution ” 
cespititium. 
Selaginella 
helvetica, 
of O, in 1 day weak and in 2-3 days active 
in all living cells. As in Dicranum, many 
cells die without assimilation returning, but 
most plants recover. 
No evolution of O, fairly active in 3 to 4 h. 
at 20? C., quite in à to 1 h. Almost all 
leaves and leaf-cells living. 
i 
{ 
i 
Most leaves living. No evo- 
lution of O, weak in'3 hrs., 
fairly active in parts in 
5 hrs., in many 
In 1 day evolu 
normal. 
still weak. 
tion of O 
