164 



MacDOUGAL and SPOEHR— components AND 



TABLE XI. 



Swelling of Dried Agar Plates at 15° C. in Solutions of CaCOH), 

 WHICH WERE Renewed Ev-ery 12 Hours. 



The augmentinig effect of calcium hydroxide which was found in 

 concentrations of o.oooi is here seen not to be exhibited in a sokition 

 containing twice this amount, and is not increased when a reduction 

 below this concentration is made. 



The effects of ammonium hydroxide and aniline on the swelling 

 of agar are of direct interest in any discussion of the relative action 

 of the weaker and stronger bases. 



Data for comparisons have been conveniently grouped in Table 

 XII. 



TABLE XIL 



Swelling of Dried Agar Plates at 15° C. in Solutions of Various Hy- 

 droxides, Renewed Every 12 Hours, in Terms of Water as 100. 

 Total swelling of dried agar plates in water 3,950 per cent. 



The behavior of agar in the weak bases ammonium hydroxide, 

 ethylamine and aniline on the one hand and in lithium hydroxide, 

 sodium hydroxide and potassium hydroxide on the other, exhibits 

 some interesting differences, particularly in the more dilute solu- 

 tions.^ Owing to the fact that in solutions of ammonium hydroxide 

 and ethylamine there exist equilibria respectively between dissolved 

 NH, and the hydroxide, and between dissolved C2H5NH2 and its 

 hydroxide, the condition in solutions of these substances particularly 

 in the more concentrated solutions offer a rather complicated situa- 



3 MacDougal, D. T., and Spoehr, H. A., " The Swelling of Agar in Solu- 

 tions of Amino Acids and Some Related Compounds," Bot. Gas., 69: 1920 

 (in press). 



