COLLOIDAL BEHAVIOR OF PLANT PROTOPLASM. 165 



tion not very dissimilar from that obtaining in solutions of the 

 amino acids. It will be recalled that aniline is a weaker base than 

 ammonium hydroxide while ethylamine and the hydroxides of lith- 

 ium, sodium and potassium are stronger. 



Effect of Included Bases on Swelling of Biocolloids. 



The hydration of plates or sections of dried colloids in solutions 

 involves questions of penetration and of the formation of com- 

 pounds in the external parts of the section which may modify the 

 hydration of the interior of the mass. The conclusion was reached 

 in work set forth in previous papers that acids, metallic salts and 



TABLE XIIL 



Swellings of Dried Sections of Bicolloids with Included Bases in Per- 

 centages OF Original Thickness. 



HCl o.oi N. 



KOH O.OI N. 



Histidine Dihydro- 

 chloride o.oi N. 



Glycocoll O.OI N. 



Water. 



Agar 2, Gelatine 3, KOH 0.000,05 N 

 NaOH 0.000,025 N 

 Ca(0H)2 0.000,025 N 

 Sections o.i mm. Thick at 16-17° C. 



2,100-3,220 



2,950-3.570 



1,700-2,050 



2.750-3.030 



2,050-2,380 



Agar 3, Gelatine 3, KOH o.ooi N 

 NaOH o.oooi N 

 Ca(OH)o0.oooi N 

 Histidine 0.001,4 

 Section 0.09 mm. Thick at 16-17° C. 



850-875 



2,220-2,680 



1,700-1,800 



2,050-2,260 



Agar 3, Gelatine 2, KOH 0.000,05 N 

 NaOH 0.000,025 N 

 Ca( OH) 2 0.000,025 N 

 Sections 0.14-0.15 mm. Thick at 15° C. 



500-521 



2,330-2,820 



1.570-1,730 



2.850-3,200 



2,300-2,780 



amino-compounds incorporated in colloids exerted a greater effect, 

 generally a lessening action on swelling than the same amount of the 

 reagent applied in aqueous solution. 



Furthermore it may be said in particular that in no case did an 



PROC. AMER. PHIL. SOC, VOL. LVIII, K, JUNE 2, I92O 



