ON BICOLLOIDS AND CELL xMASSES. 



19 



hydroxides at o.oi A^ the metals exert a lessening effect on hydra- 

 tion in a series which runs Ca, K, Na with the least swelling in the 

 calcium. In the chlorides at o.oi M the scries runs Ca, K, Na, a 

 coincidence strongly suggestive of the specific action of the bases or 

 cations, which has eluded many experimenters. 



Sections of the agar Plate B were also swelled in nitrates and 

 sulfates of sodium and potassium at 14-15° C. with increases as 

 noted in Table II. 



TABLE IL 



It is to be seen that swelling in the sulfates does not exceed the 

 amount possible in water even in the dilute solution, while at 

 0.0001 M the swelling in the nitrates of both sodium and potassium 

 is in excess of that possible in water. 



The eft'ect of the salts on gelatine is one which has received at- 

 tention at the hands of many investigators, but the recently pub- 

 lished results of Loeb on the action of these substances at the low 

 concentrations which may be of biological interest are the most de- 

 cisive yet available.^ However, it was deemed important to carry 

 out swellings of sections of this substance by the auxographic 

 method in order to secure data strictly comparable with those ob- 

 tained from the tests with agar. The gelatine was of a sample 

 which, made up in an 8 per cent, solution, had a Ph value of 5.2 

 Sections 0.27 mm. in thickness were swelled at 14-15° C. and in- 

 creases were noted in Table III. 



The hydration of gelatine as illustrated by the action of the HCl 

 is increased by H or OH ions, the effect rising with the departure 

 from the isoelectric point. Thus the swelling in the acid at o.oooi 

 M Ph value of 4.2 is scarcely more than in water, while at o.oi M 

 with a Ph value of 2.01 the swelling is over four times as great as 



^ Loeb, J., "The Action of Salts in Low Concentrations,"' Jour. Gen. 

 Physiol., 3: 391, 1921. 



