83 



plants when the soil air contained 80 petfcent carbon 

 dioxide and 20 percent air. Similarly in the experiments 

 of Kosaroff 1 , later described in detail 2 , carbon dioxide 

 caused a greater interference with water-absorption by 

 roots than was caused by simple deprivation from oxygen. 

 This was true both iii soil and in water-cultures. Simi- 

 lar injuries by passing carbon dioxide through the cul- 

 ture solution of water-culture have been observed by Wolf^ 



4 /*■ 5 



and by Free . Bifcner and Lucanus , however, observed 



an increased growth on passing carbon dioxide through 



the culture solution. 



In soil cultures, lloyes 6 has found wilting 



and bad growth of corn and tomato plants when the soil 



was saturated with carboii dioxide. On the other hand a 



number of investigators have obtained increased yields 



of various crops by blowing carbon dioxide through the 



1. Diss., Leipzig, pp. 47-62 (1897 J; Bot. 

 Gentbl. 85: 138-144 (1900). 



2. See page • 



3. Jahresber. Agriculturchem. 18 70-1872: 134. 

 4* Johns Hopkins Univ., Girc. : 



(1917 J, 



5. Landw. Vers. Stat. 8: 128-177 (1866). 



6. Science 40: 792 (1914). 



