ON BICOLLOIDS AND CELL MASSES. 29 



tions in the electromotive series when used as hydroxides, give the 

 same relative action when used as chlorides. The series runs Ca, K, 

 Na, the greatest retardation being effected by the calcium and the 

 least by sodium, when used at concentrations of o.oi M. 



2. Reversed effects by which hydration of agar is increased are 

 shown by the hydroxides at o.ooi A'', as described in a previous con- 

 tribution, but no well-defined dift'erences among the bases used 

 could be made out. Similar reversed effects were exhibited by the 

 chlorides of calcium, magnesium, potassium and sodium at o.oooi M 

 and by potassium and sodium in concentrations as great as o.ooi M. 



3. Purified agar used in the experiments has a PH value of 6.5, 

 also swells more in HCl at a PH value of 4.2 than in water, a state- 

 ment to be applied in correction of various conclusions in previous 

 papers. 



4. Purified agar shows exaggerated swellings in a series of acid, 

 salt and hydroxide solutions in which the hydrogen ion concentration 

 ranges from PH 4.2 to 11. 



5. Purified agar also shows exaggerated swellings in sodium and 

 potassium nitrates at o.oooi M but not in the sulphates. 



6. Of the chlorides of calcium and potassium and hydrochloric 

 acid at concentrations from o.oi M to o.oooi M only KCl at o.ooi 

 and O.OOOI M increase the swelling of an agar-gelatine mixture. In 

 a similar series only KCl at o.oooi M increases swelling in a gela- 

 tine-agar mixture. 



7. Agar plates with included chlorides at concentrations increas- 

 ing swelling, when applied as hydrating solutions showed exag- 

 gerated swelling in HCl, NaCl, KCl at 0.0001 M, but a lessened 

 swelling in CaCL and MgCU at this concentration. 



8. Gelatine plates with incorporated salts as above showed 

 swelling in HCl increasing with the concentration beginning with 

 the O.OOI M solution, in reverse of the action of the CaCL solution 

 which was greatest but still less than in water until at o.oooi M. 

 Swelling in KCl did not exceed that in water until a concentration of 

 O.OI M was reached. 



9. The maximum swelling of a gelatine (3 parts) -agar (2 

 parts) plate is greatest in HCl o.oi A^, KCl o.ooi M and CaCU at 

 O.OOOI M. 



