82 



of spores of mucor and of some pollen grains. Crocker, 

 however, states that some seeds cannot he rendered dormant 

 by carbon dioxide. 3?he experimental result of Babcock^ 

 that seeds die more quickly when stored in carbon dioxide 

 than in air, may be simply a result of cessation of re- 

 spiration because of the absence of oxygen. Among 

 specific effects of carbon dioxide in the animal organism 

 there may be mentioned its reported action in stimulating 

 the respiratory center* and its probable influence on the 

 tonus of the intestine. ^ 



The evidence concerning the action of carbon 

 dioxide on roots is even more inconsistent than thai; with 

 regard to its effects on the aerial portions. Thus 

 Jentys 5 and Chapin 6 have obtained injuries to roots by 

 carbon dioxide and Kossowitsch observed wilting of pea 



1. Amer. Jour. B?t. 3: 115 (1916). 



S. Wise. Agr. Exp. Sta., Res. Bull. 22, p. 

 98-101 (1912). 



3. Laqueur and Verzan,- Pflug. Arch. 143: 395- 

 427 (1912). 



4. Rona,- Zentbl. Physiol. 26_ : 733-734 (lyi2). 



5. Bull. Acad. Sci. Cracovie : 306-310 



(1892); Bot. Gentbl. 52: y3 (1892). 



6. Flora 91: 348-379 (1902). 



7. Bot. 2tg. : 702 (1892). 



