Periodical Literature. 327 



tips indicates that the oxidizing activity is insufficient to decrease 

 the harmful effect of the bog toxins. 



"5. It is possible that ecesis, association and succession of 

 plants depends primarily upon respiration, and that in respiration 

 bog plants differ from other plants. 



"6. Treating bog water with an insoluble absorbing agent is 

 invariably beneficial. 



"7. Different physiological phases result from the progressive 

 addition of an absorbing substance. With coarser-grained ma- 

 terials, the low optimum rate of transpiration is soon succeeded 

 by a minimum, which is due to the action of toxic substances 

 still present. 



"8. Finer-grained insoluble bodies are more beneficial. The 

 response to toxic bodies when present in small amounts leads to 

 acceleration of growth. The period of growth is more prolonged, 

 and the optimum and maximum rate of transpiration lie near to- 

 gether. 



"9. The adsorptive action of carborundum and humus is about 

 four times greater than that of quartz ; the capacity of soils for 

 retaining toxins is therefore higher the greater the content of 

 humus. 



"10. The decrease of the poisonous effect of bog water is 

 probably a function of the surface of the particles ; it is rela- 

 tively proportionate to the quantity of the solid body used. 



"11. In agricultural soils used as adsorbents, the presence of 

 the adsorbed unknown toxins replaces normal growth by an 

 abnormal retardation. Fertility is restored through aeration, 

 that is, after time enough has elapsed for the oxidation of the 

 injurious bodies. 



"12. The contaminated condition of agricultural soils and the 

 consequent decreased physiological activity of the plants grown 

 in them still further indicates that xerophily cannot be due to 

 acidity ; that is, the factors heretofore cited are only in part the 

 cause of xerophily." 



Bog Toxins and their Effect upon Soils. Botanical Gazette, May, 1909, 

 pp. 387-405- 



