21 



unknown. But certain soils possess this power in 

 much higher degree than others. It is possible, there- 

 fore, that the ability of a root to live under condi- 

 tions of deficient aeration may depend not only on 

 the nature of the root and its own capacity for dis- 

 posing of its intermediate respiration products, but 

 also on the soil, through the degree to which it may 

 possess the power of removing or rendering harmless 

 the toxins excreted hy the root. The available experi- 

 mental data do not permit the discussion of these pos- 

 sible mutual effects of soil and plant on anaerobiosis o/- 

 roots except in the most tentative and speculative way, 

 but it is obvious that many varied behaviors are 

 theoretically possible. 



It is apparent, at the least, that the facts 

 of respiration do not furnish a sound basis for as- 

 suming that all roo$s must be supplied with atmospheric 



1. True and Oglevee,- Bot. Gaz. 39: 1-21 

 (1905 J; Konig,- landw. Vers. Stat. 66: 401-461 (1907); 

 Schreiner and Reed,- Jour. Biol. Chem.3: xxiv-xxv (1907J, 

 Jour. Amer. Ghem. Soc. 30: 85-97 (1908), Bot. Gaz. 47 : 

 355-388 (1909), U. 3. Bur. of Soils, Bull. 56, 52 pp., 

 1909; Schreiner and Sullivan,- U. S. Bur. of Soils, 

 Bull. 73, 57 pp., 1910, Bot. Gaz. 51: 121-130 (1911); 

 Sullivan,- Jour. Biol. Ghem. 6_: xliv (1909); Sullivan, 

 and Raid,- Jour. Ind. and Eag, Chem. 3: 25*30 (1911). 



