EFFECT OF BOG WATER ON SWELLING 89 



materials which make up the protoplasm of a plant were com- 

 bined in the form of an elastic gel such a mass should show water- 

 relations similar to those of the plant. This reasoning was 

 justified by actual experience.^ Diversified experimentation 

 leads to the conclusion that a mixture of 80 to 90 parts of 

 agar and 10 to 20 parts of albumen, gelatine, or albumen deriva- 

 tives mipregnated with the nutrient salts in a proportion 

 decreasing to the vanishing point, simulates the swelling action 

 i^ the protoplasm of roots and stems of the higher plants tested.^ 



The chief organic constituents may vary so widely in amount 

 however that the proteins may be present in greater proportion, 

 as in the case of pollen cells, or in bacteria in which the albumen 

 content is very high. The proportions of the amorphous carbo- 

 hydrates and proteins, the concentration of the included salts 

 acidity, temperature, viscosity, previous history, and the com- 

 position of the solutions in contact with the protoplasm are all 

 features which play a part in determining the amount and 

 nature of the swelling. The swelling of biocolloids and of 

 plants may therefore be expected to yield suggestions as to the 

 character of the solutions in which it takes place. 



The general methods of preparing the biocolloids has been de- 

 scribed in the two papers to which reference has been made. 

 The completion of the preparation puts the experimenter in 

 possession of dried plates from which small sections, 3 by 4 mm. 

 and not more than 0.2 nam. in thickness, may be cut. A trio of 

 these may be placed in a stender dish and subjected to the 

 action of water or solutions in the same manner as sections of 

 living and dried plants may be treated. 



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

 sample from Ronalds, in the region of Seattle, Washington. Mr. 

 J. M. ]\IcGee of the Department of Chemistry of the University 

 of California, reports the following constituents : 



'See MacDougal and Spoehr. Growth and imbibition. Proc. Amer. Phil. 

 Sec, 56:335-338. 1917. 



•* See MacDougal and Spoehr. The effects of acids and salts on biocolloids. 

 Science, 42: 269. 1917. 



