19 iq] RIGG 6- THOMPSON— BOG WATER 375 



nitrogen in these conditions is apparently influenced to a large 

 extent by immediate local conditions. 



Klein (9) was the first one to suggest that the toxicity of bog 

 water is due to the presence of chemical combinations harmful to 

 plant hfe. The water from a black bog overflowed into the 

 meadows of a certain portion of East Prussia, causing consid- 

 erable damage. He analyzed this water and found. 312.8 parts 

 per million of organic matter and 175.9 parts per million of 

 inorganic matter. Among the reasons which he points out as to 

 why this water is injurious to crop production these two are 

 of special interest: (i) it acts as a reducing agent, (2) it pro- 

 duces chemical compounds that are harmful to plant life. The 

 bog he studied differed from Puget Sound bogs in having con- 

 siderable mineral content. Our bogs and his have in common 

 the avidity of the organic matter for oxygen. His suggestion 

 of toxicity is the earliest one seen by the authors. The review 

 of his work says that when exposed to air the moist peat soon 

 took up oxygen, with the result that there was formed on the 

 surface of the soil a hard crust which was "impervious to the 

 oxygen of the air, and the humus, withdrawing oxygen from 

 the iron compounds, formed salts destructive to vegetable hfe." 

 It does not seem positive from this wording whether the "salts 

 destructive to vegetable life" came from the iron compounds or 

 from the humus. 



Previously published results (15) indicating that the osmotic 

 pressure of bog water is very low had suggested that the material 

 in solution in it is probably in a colloidal state. The data given 

 seem to confirm this view, while the experiments with Trades- 

 cantia cuttings indicate that the matter in the colloidal state is a 

 large factor in the toxicity of the water. 



Bauman and Gully (i) have shown that the acidity of bog 

 water is due to the colloidal material of the cell walls of the hyaline 

 cells of sphagnum. This would seem to suggest that both the 

 acidity and the colloidal properties of bog water are due to the 

 breaking down of sphagnum. The senior author has suggested 

 in an earlier paper (10) that since the essential conditions for the 

 formation of a bog are the continued growth of sphagnum and the 



