346 B. E. LIVINGSTON AND W. E. TOTTINGHAM 
yet ionic nor even molecular, proportions that determine the physiolog- 
ical properties of a solution. The problem thus emphasized is as 
important in agricultural practice as it is complicated and difficult. 
The work of many investigators will be required in this field before 
any serious discussion of the salt-nutrition of plants may even be at- 
tempted. It is to be hoped that the results of such work may be 
allowed to appear as the work goes on, so that our general appreciation 
of this exceedingly fundamental problem in agricultural science may 
begin to assume definite form as soon as possible. Thus only can 
enormous waste of time and human energy, due to our lack of appre- 
ciation of these matters, be avoided. 
Laboratory of Plant Physiology 
OF THE Johns Hopkins University, 
Department of Agricultural Chemistry, 
University of Wisconsin 
