THE 
NEW PHYTOIiOGIST. 
Vol. XVI, Nos. 8 & 9. Oct. & Nov., 1917. 
[Published November 14th, 1917.] 
OBSERVATIONS ON THE INFLUENCE OF AERATION 
OF THE NUTRIENT SOLUTION IN 
WATER CULTURE EXPERIMENTS, WITH SOME 
REMARKS ON THE WATER CULTURE METHOD, 
By Walter Stiles and Ingvar Jorgensen. 
General Introduction. 
I NVESTIGATIONS dealing with the growth of plants in water 
cultures have been pursued now for more than two hundred 
years since Woodward carried out his experiments at the end of the 
seventeenth century. During that time such studies have passed 
through various phases, from the first crude observations to the more 
definite experiments which resulted from the development of the 
water culture method after the successful part it played in the 
controversy regarding the essential elements for plant nutrition and 
growth. The technique of the water culture method as it is 
employed at present was chiefly developed by Sachs. Later 
investigators have introduced various slight alterations in the 
technique, but in its broad principles the water culture method 
remains today much the same as Sachs left it. It is, in short, 
included in the general stagnation which has characterised plant 
physiology during the last fifty years. 
The essential of the water culture method has been to give a 
plant a nutrient solution of a definite composition and after an 
arbitrary time to measure the dry weight of the plant. There is 
no attempt to control any factor except that of the nutrient medium 
surrounding the roots, or to take account of any process beyond that 
of growth as measured by increase of dry matter. 
Such methods should not be used without reference to the other 
factors influencing the life of the plant, or without examining how 
the life of the plant is influenced in its various phases. Our whole 
outlook on the physiology of the plant, resulting as it does, from 
