17 



cells, and consequently the amount of Trater contained in 

 the tissues, would be much greater nhere there was but 

 little loss by transpiration. The percentage of ash in 

 dry matter also varied in the plants gro?m under the diff- 

 erent conditions. 



It is significant to note that in every instance, com- 

 paring the plants grown under dry and moist conditions, 

 the higher percentage of ash in dry matter is coincident 

 with a lower yield of total dry matter, tho the total 

 amounts of ash constituents are practically the same under 

 both conditions. This appears to indicate that the con- 

 ditions which are unfavorable for growth inhibit the elab- 

 oration of organic food substances to a greater degree than 

 the absoprtion of mineral salts. 



It will be observed that transpiration was not en- 

 tirely ohecl!:ed in the moist atmosphere. This is in accor- 

 dance with the view generally held by plant physiologists 

 that, in the presence of svmlight, the temperature of the 

 plant usually rises above that of the surrounding air and 

 that under these conditions transpiration may be carried on 

 to a slight degree even in an atmosphere saturated with 

 moisture. 



