77 



to have favorable effects on growth. 1 Larger increases 

 are injurious 2 , There is much conflict of evidence as 

 to the precise percentage of carbon dioxide in the air 

 which is most favorable to plants, this conflict being 

 due, probably, to the fact that this optimum concentration 



T~. Godlewski,- Arb. bot. Inst. Wurzburg 1: 343 

 (1373), 2: 495 (1880); ' Kreussler,- Landw. Jahrb. 14: 

 913 (1885), 16: 711 (1887), 17: 161 (1888), 19: 64y 



(1890); Jentys,- Bull. Acad. Sci. Cracovie : 306- 



310 (189E); Chapin,- Flora 91: 348-379 ( 190E ) ; Deraoussey,- 

 C. H. 136: 3E5-328 (Iy03), 138: 291-S93 (1904); 159 : 

 883-885 (1904); Jardin,- 18: SSI (1904); Fischer,- Sar- 

 tenflora 61: Sv8-307 (1912), Jahresber. Yer. Angew. Bot. 

 11 ; 1-8 (1913), Gartenflora 63: 125-132 (1914); ilisselew,. 

 Bot. Centbl., Beih. 32: 86-96 (1914). 



S. See the articles of Godlewski and of Chapin 

 cited ei a pa ge /Tt ^ note , and de Saussure,- 

 Rech arches chimigues, pp. S5-34 (1804); Grischow,- 

 Unters uber d. Athmung, p. 33 (1819); Davy,- Elements 

 of Agric. Ghem. 3rd ed., p. S05 (18S1); Boussingault,- 

 Agronomie, vol. 4, pp. 286 ff (1868); Bohm,- Sitsungsber. 

 Akad. V/iss., V/ien, Abt. 1, 66: 18 (1872 J; Mflller,- Bot. 

 Unters., vol._JL, p. 353 (1876); De Vries,- Landw. Jahrb. 

 8: 417 (1879); Frank,- Krankheiten der .-flanzen, End ed. , 

 vol. 1, p. 307 (1894); Freudenreich,- Bot. Centbl., Beih. 

 4: 457 (1894); Lopriore,- Jahrb. wiss. Bot. . 8 : 531-6;:c 



