68 Hydration and Growth. 



The numerous analyses of the water have failed to disclose physico- 

 chemical features which might be held responsible for the very direct 

 and positive action exercised in the determination of the plant form- 

 ations of such places. The history of such attempts is a long one. 1 

 Bog water was furnished by Mr. E. R. Long, who procured a sample 

 from Ronalds, in the region of Seattle, Washington. Dr. J. M. McGee 

 reports the following constituents per liter: 



TABLE 55. gm. 



Organic matter . 106 



Ash (chiefly CaSO 4 ) 048 



Total soluble residue 154 



Swamp water was procured by the kindness of Dr. S. A. Gortner, who 

 obtained a sample from near Anoka, Minnesota, concerning which he 

 says: 



"This sample was taken about 20 miles north of Minneapolis, in Anoka 

 County, of which three-fourths of the area consists of peat lands. These 

 peat lands are of the grass and sedge formation, the peat being from 4 to 6 

 inches or more deep, fairly well decomposed, and one of the better grades of 

 peat for agricultural purposes in that it contains an appreciable amount of 

 lime. I believe that you will find this sample of water perfectly typical of 

 most of the large grass bogs of Minnesota." 



The analysis of this water shows the following per liter: 



TABLE 56. gm. 



Soluble organic matter . 094 



Ash (CaSO 4 with trace of NaCl) 128 



Total soluble residue 222 



The degree of acidity of the bog water was such that 1.1 c.c. of N/10 

 potassium hydrate was necessary to neutralize 100 c.c. of water. The 

 acidity of the grass-sedge water was scarcely a third of this, but 0.35 

 c.c. N/10 potassium hydrate being necessary to neutralize 100 c.c. 



The first trial of the action of these waters and comparative solutions 

 was made with living material. Circular disks 12 mm. across and of 

 an average thickness of 11 to 13 mm. were cut from joints of Opuntia 

 discata which had matured at Carmel, California, in the summer of 

 1917. Tests were made with water, swamp water, bog water, and 

 various calcium solutions at 15 C. The measurements obtained were 



as follows: 



TABLE 57. p. ct. 



Distilled water 18.2 



Swamp water 13.6 



Bog water 18.3 



Calcium nitrate, 0.008 M 15 . 5 



Calcium nitrate, 0.008 M acidified with nitric acid 16.8 



Calcium nitrate, 2 M (shrinkage and subsequent swelling) 6.8 



Calcium nitrate, 0.2 M (steady shrinkage) 



Calcium nitrate, 0.02 M 14 . 6 



Calcium nitrate, 0.002 M 15.5 



Calcium nitrate, 0.0002 M 21 



1 See Rigg, G. B., Summary of bog theories. Plant World, 19:310, 1916. 



