THE ACTION OF BASES AND SALTS ON BIOCOLLOIDS 

 AND CELL-MASSES. 



By D. T. MACDOUGAL. 



(Read April 21, 192 1.) 



The suggestion was made in an earlier paper that the common 

 metals which enter into nutrient solutions might find their chief 

 importance in restricting, limiting or defining hydration of the cell- 

 colloids.^ MacDougal and Spoehr carried out a series of tests upon 

 this matter and found in fact that the strong metallic bases when 

 used at concentrations of 0.0 1 A'^ do limit or restrict the hydration of 

 agar according to their place in the electromotive series, the least 

 swelling taking place under the action of the strongest base, with 

 rubidium unplaced. Beginning with the strongest the series runs 

 K(Rb)NaLi, and if calcium were added to the series the swelling 

 under its action was less than that in potassium. - 



When the concentrations were reduced however to o.ooi A^ it 

 was found that hydroxides of all of the metals increased the hydra- 

 tion capacity of agar. This was of importance as a review of all of 

 the available data seems to show that the range of the H^-OH" bal- 

 ance in the plant cell lies between the values expressed by Ph3 and 

 Ph II, or between about o.oi M aspartic, succinic or propionic acid 

 and under o.ooi N KOH. 



The reversal of efifects at great attenuations in the hydroxides 

 led to the extension of auxographic measurements upon the efifects 

 of low concentrations of the salts which are of such interest and im- 

 portance in cultures, and the action of chlorides, nitrates and sul- 

 fates of potassium, calcium, sodium and magnesium upon agar, 

 gelatine and mixtures was made at Carmel in the summer of 1920. 



1 MacDougal, D. T., "Growth in Organisms," Science, 49: 599-605. 1919. 

 (See page 11 of reprint.) 



2 MacDougal, D. T., and H. A. Spoehr, " The Components and Colloidal 

 Behavior of Plant Protoplasm," Proc. Amer. Phil. Soc, 59: 154, No. i, 1920. 



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PROC. AMER. PHIL. SOC, VOL. LX, B, JULY 25, I92I. 



