378 BOTANICAL GAZETTE [November 



In the main, however, the success that has been attained in 



the cultivation of bog lands in the Puget Sound region has been 



attained by the use of acid-tolerant crops (3) such as cranberries, 



strawberries, celery, onions, lettuce, cabbage, and carrots, rather 



than by correcting the acidity in order to grow crops that are not 



acid tolerant. 



Summary 



1. Bog water gives a precipitate on standing a few hours 

 after saturation with electrolytes. 



2. It also gives a precipitate on standing a year or more with- 

 out electrolytes. 



3. The filtrate from the precipitation with (NH4)2S04, when 

 dialyzed until free from sulphates, is not toxic to the root hairs of 

 Tradescantia cuttings. 



4. Bog water, when dialyzed for the same length of time as 

 this filtrate, is toxic to these root hairs. 



5. The distillate from bog water gives no precipitate with 

 electrolytes, is much less acid than bog water, and is not toxic to 

 these root hairs. 



6. The concentrate obtained when bog water is distilled to 

 approximately one-sixth of its original volume gives a heavier 

 precipitate with electrolytes than does bog water. It is also more 

 acid and more toxic to these root hairs. 



7. The residue from complete evaporation of bog water is a 

 brownish powder which is soluble in cold water, insoluble in 

 alcohol and gasoline, and practically insoluble in ether. 



8. This water solution of the residue is toxic to the root 

 hairs of Tradescantia. 



9. No solid matter was thrown out of bog water by centrifuging. 

 ID. Chemical analyses of Puget Sound bog waters give results 



similar to those reported for other American bog waters. 



11. The toxicity of bog water to Tradescantia cuttings seems 

 to be connected with the matter in it that is in a colloidal state. 



12. The oxidation of this toxic matter to non-toxic matter 

 seems to be a basis of agricultural practice in bringing bog lands 

 into cultivation. 



University of Washington 

 Seattle, Wash. 



