PHYSIOLOGY OF NUTRITION. 



reduce them as quickly 

 as possible to the air- 

 dry condition by ex- 

 posure to the air, then 

 with scissors cut up 

 each plant separately 

 as finely as possible, 

 and use either the 

 whole mass of an indi- 

 vidual or a weighed 

 portion of the air-dry 

 substance for the de- 

 termination of the dry 

 weight. 



If we compare the 

 dry weight of a plant 

 with that of the seed, 

 we find that the former 

 is many times greater 

 than the latter. Since 

 the ash of the plants 

 obtained, like that of 

 the seed, is relatively 

 very small in quantity, 

 it follows that a large 

 quantity of organic sub- 

 stance has been pro- 

 duced by our plants. 

 We have however 

 placed at their disposal 

 no organic substances, 

 but merely water, some 

 salts, and the consti- 

 tuents of the air. And 

 our cultures therefore 

 indicate that the re- 

 search objects used are 

 able to produce organic 

 bodies from purely in- 

 organic material. 

 If it is proposed to make extended water-culture investigations, 



FIG. 1. Maize plant, developed by the water-culture 

 method. 



