28 BOTANICAL GAZETTE [JULY 
intensity do not occur simultaneously, and may be in opposite 
directions. 
4. The respiratory quotient and respiratory intensity vary 
markedly for different seeds, and in the Rosaceae for different lots 
of the same kind of seed under precisely similar experimental con- 
ditions. The respiratory quotient in Amaranthus and Chenopodium 
is markedly stable. Since in the Rosaceae the embryo is dormant, 
while in the other two seeds it is not, it may be that this difference 
in behavior is characteristic of seeds with dormant embryos, and 
the greater stability of respiration in Amaranthus and in Cheno- 
podium represents the attainment of a more stable metabolism in 
these seeds. 
5. Stability or variability of the quotient may be of signifi- 
cance as indicative of the possibility of an interplay of several 
factors on the metabolism. In Crataegus, and presumably in the 
other Rosaceae, the marked variability is probably the resultant 
between the respiration of the dormant hypocotyl and that of the 
mature cotyledons. 
6. The arrangement of the respiratory quotients for each seed 
in a curve showing the percentages of the experiments with each 
seed giving each value, and in frequency histograms in which are 
plotted the actual number of experiments in which each quotient 
value occurred, indicates the tendency of each seed toward a 
typical respiration. The quotients for Chenopodium and Amaran- 
thus are 0.928 and 0.856 respectively, while those of the Rosaceae 
form three groups within a range of 0.118. In the first group, 
between 0.648 and 0.7, fall the quotients for apricot, peach, and 
blue gage plum; in the third, between 0.8 and 0.876, those of 
cherry and sand-cherry; while that of hawthorn, 0.774, lies mid- 
way between. 
Grateful acknowledgment is made to Professor WILLIAM 
CRocKER and to Dr. Sopuia H. Eckerson for the suggestion and 
the direction of this study, and to Dr. B. I. Mrzter for her assist- 
ance in graphing the data. 
UNIVERSITY OF CHICAGO 
