A SUMMARY OF BOG THEORIES 317 



j. Lack of aeration of the substratum. This factor has the 

 approval of Transeaii (58, p. 38), Friih and Schroeter (23), 

 and Whitford (63, p. 314). Dachnowski (15, p. 141) states: 

 " . . . . results reported as due to lack of aeration in 

 the bog substratum are really due to toxicity." Transeau (58, 

 p. 39) finds that lack of aeration favors the growth of mycorrhiza 

 on roots of Larix. This may suggest a question as to whether 

 the growth of mycorrhiza in bogs inhibits mesophytes or at least 

 gives advantage to xerophytes. Nabokisch (34) believes that 

 intramolecular respiration in low oxygen pressure gives rise 

 to products that are toxic when concentrated, though stimula- 

 tory when dilute. It seems probable to the ^\Titer that lack 

 of aeration is a factor, at least indirectly. 



k. Abundance of methane. It is of course well known that 

 methane is formed by decay with deficient supply of oxygen. 

 An inflammable gas has been obtained by thrusting a piece of 

 gas pipe or in some cases even a pole into bogs in the Puget Sound 

 region. The writer has seen no evidence as to how much influ- 

 ence this factor may have. It should be considered in con- 

 nection with (j). 



I. Deficiency in "available" nitrogen. Transeau (58, p. 37) 

 makes the statement that "Bog soils are notable deficient in 

 . . . . available nitrogen." Jodidi (30) found no nitrates 

 in the Michigan peat soils examined. He found that practically 

 all of the nitrogen was of organic nature and that the amount 

 of water-soluble nitrogen increased slowly with weathering. He 

 says that the amount of ammonia ("representing the nitrogen 

 immediately available as plant food") is sufficient in brown peat 

 to provide for one or two crops under cultivation. He found 

 monamino acids, amides and diamino acids. 



Robinson (45) found that 25 per cent of the nitrogen of peat 

 is converted by hydrolysis into primary amines, probable form- 

 ing amino acids, and that 10% is present as acid amides. He 

 says that the greater part of the nitrogen in peat occurs in numer- 

 ous unknown forms, "which may represent the most important 

 factors in aiding or inhibiting plant growth." He expresses 

 the belief that the greatest need at present in determining the 



