45° BOTANICAL GAZETTE [DECEMBER 
logical advance is not possible until we make a direct attack 
from the ecological standpoint upon the subject of the investi- 
gation and representation of the facts of the environment, 
especially of the soil. Now this obviously cannot be done, as 
most ecological work is now being done, by busy teachers who 
can devote to field work only a few weeks of their summer vaca- 
tions. It can only be accomplished by the systematic work of 
trained investigators, who, with a fully and properly equipped 
laboratory established in the field at the place to be investigated, 
and with ample assistance to aid in the mechanical work, can 
devote their entire time to the subject for months or years until 
the problems are solved for that region. The laboratory must 
obviously be in the field, since the conditions vary so much in 
the different seasons and under the various local conditions. 
Thus, and thus only, I believe, can we make any further real 
advance in ecological plant-geography. 
Third, there must be made a thorough study not only of the 
structure and development of the important plants which give 
character to the different parts of a vegetation, but also of their 
physiological characteristics quantitatively expressed. Thus, we 
need to know for each kind of dominant plant its transpiration 
power, and the extent of its possible regulation under various 
circumstances ; its water-absorbing power ; its capacity for air 
storage; its power and limits of resistance to salt or other unfavor- 
able substances and influences; its cardinal temperature-points 
for growth and for its other physiological properties. For this 
study it is indispensable that methods and apparatus be devel- 
oped by which the various facts may be ascertained with ease 
and precision, and the results expressed or represented in a form 
to make them available for ecological use, that is, so that they 
may be compared and correlated with the physical data. Very 
important in this connection is the determination of the physio- 
logical plasticity of the plant, and in how far adaptation to 4 
new influence weakens or destroys adaptation to an older. 
Hitherto, in our studies of adaptation we have laid great stress 
upon the study of structures in relation to adaptation to environ- 
ment, and much knowledge of this subject has been accumu- 
