UTAH ACADEMY OF SCIENCES 75 
DISTILLED WATER AS A MEDIUM FOR 
GROWING PLANTS. 
BY M. C. MERRILL. 
Because of the extensive use of distilled water as a 
medium in which to grow plants for comparative pur- 
poses in solution-culture work, it was felt that there was 
justification for experimental work in order to determine 
more definitely the relation of plants to this medium. 
This paper will deal with the methods of work and the 
results obtained from the standpoint of growth relations 
and also by means of the effect produced upon the 
medium as determined by means of electrical conduc- 
tivity measurements. 
1. HISTORICAL. 
The relation of plants to distilled water is a matter 
that has been under more or less serious consideration 
at different periods for a long time. As early as 1691- 
1692 Woodward, who first employed the method of water 
culture in his interesting experiments, found that plants 
grew better in river water than in either rain water, 
spring water, or distilled water. The difference was 
of course due to the quantity of plant food contained 
in the medium, and this idea, coupled also with the char- 
acter of the nutrients, has been the basis for a vast 
amount of physiological work since that time. 
A review of the literature on the subject shows that 
three main views have been entertained as the reason 
why plants and animals thrive better in natural water 
or aqueous media than in distilled water. These views 
are: 
Because distilled water lacks essential nutrients; 
Because it contains deleterious substances; 
Because of the extraction or exosmosis of salts, or 
Co no 
