330 BOTANICAL GAZETTE [APRIL 
diurnal minimum in the water content of foliage leaves, a criterion 
that may be of some importance to scientific agriculture, at least 
in the arid regions of the globe. By this criterion it may be pos- 
sible to determine indirectly, and somewhat simply, the status of 
the water relations of the plant, and indeed to foresee the need of 
increased soil moisture, long before the usual criterion of cessation 
_of growth or actual wilting becomes manifest. 
THE Jouns Hopkins UNIVERSITY 
BALTIMORE, Mp 
BuREAU OF SCIENCE 
Mania, P.I. 
