41 



synthesis and will vary, therefore, with the condition 

 of the plant, the time of day, and the intensity of 

 light. Data as to the inner air of water plants is simi- 

 larly conflict ing-*- and for similar reasons. 



The cultural evidence suggesting the necessity 

 of soil aeration would be better described by aaying 

 that it suggests the unsuitability of soils which are 

 water-logged. The extreme case is that of swamp soiis 

 which are inhospitable to most dry-^and plants though 

 possessing a rich special flora of their own. Of im- 

 portant agricultural plants only rice, asparagus and the 

 cranberry will grow successfully on such soils. Less 

 extreme cases of bad drainage and high water-table are 

 common everywhere and such soils are almost always below 

 normal in productivity. It is the usual assumption that 

 the bad results of insufficient soil drainage are due 

 largely if not entirely, to inadequate aeration. 2 



~Tl lime,- Ann. sci. nat. (3) 2 : 536 (1841); 

 Devaux,- Aim. sci. nat. ( 7t 9: 35 (1889); Wille,- Bot. 

 Jahresbar. 1889 : 226; Loven,- Svensk. Vet. Akad. Handl., 

 Bihang. 17: (18yi); Aubert,- Rev. gen. bot. 4: 275 

 (1892). 



2. Wollny,- Exp. Sta. Rec._3: 533, 536-53 7, 541- 

 542 (1892), Forsch. G-eb. Agr. xhysik 20; 52 (1897), Fun- 

 ling' s Landw. Ztg. 48: 37 7-382, 401-405, 441-445 (1899); 

 Mangin,- G. R. 120: 1065-1068 (1895), Ann. soc. Agron. 

 (2) 1: 1-68 (1896); Walker,- Jahrb. wiss. Bot. 32: 71 



