4 
in this country no reports of extensive field trials have heretofore 
been made. 
In October, 1913, I arranged with the Standard Chemical 
Company of Pittsburgh, Penn., to make preliminary trials on 
e 
an extensive scale. In view of the cost of ium and its pre- 
parations, the reader may wonder how such an experiment could 
e undertaken. It requires about 400 tons of radiu e of 
Various other substances, especially uranium, are present in the 
material. 
Before proceeding to describe these experiments and their 
results, it is desirable to briefly summarize the results of previous 
experimental work. 
e most extensive work that has been published in English 
of the influence of radium on the growth of plants is that of 
: te of enormously excessive quantities 
Guilleminot had especially commented on the difference between 
t ects high activities. He stated th: ile a 
two centimeters, less than an inch. Roots were found to be 
