22O PICTURING MIRACLES 



water and a little of this solution added to the 

 greater proportion of the fertilizing ones. 



As early as 600 B.C., it was believed plants ob- 

 tained all their food from water. Many people are 

 surprised when told that plants cannot take up solid 

 particles of fertilizer through the roots, but must 

 have it first in solution; this fact led to the growing 

 of plants in nutrient solutions, entirely without soil, 

 of which published records were made as early as 

 1699 A * D - 



Experimental work to discover just what plants 

 need has been carried on for many years by Plant 

 Nutrition students, using water as a medium because 

 it is impossible for exact findings to get even two 

 shovelfuls of soil containing identical elements. This 

 most interesting and painstaking work has princi- 

 pally been done by germinating seeds between moist 

 blotters, then transplanting the tiny seedlings to 

 small prepared holes in corks inserted in jars, and 

 held in place by a wad of cotton. Jars of this sort are 

 fairly good if covered with black paper, keeping the 

 solution in the dark, thus preventing the formation 

 of algae. Although plants may be grown to maturity 

 in this way, it is at the best unsatisfactory. 



To obtain good results from these experiments, 

 they can hardly be carried on in smaller than twenty- 

 five gallon tanks, which may be fitted with a float 



