IIo BOTANICAL GAZETTE [FEBRUARY 
plant decline proportionally with the liberation of heat. Experi- 
ence shows that old seeds germinate less well than fresh. The 
foregoing experiments show that the heat yield is less in old than 
infresh peas. One record of mine, made up 
of many measurements, connects growth 
with these other two processes. 
Peas which had been sprouted and kept 
for four days in Dewar flasks were subse- 
quently put in moist sand to continue ger- 
mination. The peas were of two lots, those 
seus team of the 1907 crop and those of the 1909 crop. 
H One week later they were carefully taken 
up and measured. The average length of 
the 1909 seedlings was 9.70 cm., of the 1907 
seedlings 3.52 cm. The latter is scarcely 
more than 60 per cent of the former. The 
‘seedlings from the older seeds made less 
than two-thirds the growth of the seedlings 
from fresher seeds in the same length of 
time and under the same conditions. The 
accompanying diagram shows this graphi- 
Fic. 8.—Lengths of seed- cally (fig. 8). 
ee eo see wander of If the result just now described were 
days’ growth, but of differ- ‘ . : . 
otk age of seed: not consistent with the difference in heat 
yields according to the age and freshness 
of pea seeds, I should place no reliance whatever on it. As it is, 1 
do not understand why I did not test such an interesting result by 
repeated experiment, but I have not yet done so. The question 
seems to me to deserve further examination. 
ie ER 
The possible significance of heat liberation in respiration 
From the foregoing experiments, whether on germinating seeds 
or on warm-blooded animals, it appears that there is a much 
greater release of energy in the form of heat than can be or is used 
as such by the organism. Admitting that, under the extraordinary 
conditions of the experiment, the mouse previously described may 
not have behaved normally in any respect, and that the production 
and loss of heat may have been excessive, it is nevertheless evident 
