Heterotropic Action of Colloidal Bodies. 245 



and swelled in water. Similar increases occurred when old plates 

 were hydrated in chlorides of K, Na, Mg and Ca at 0.0001 M. 



The effects of age on gelatine plates are not so marked but 

 the areal swelling increases with age. The differential effects of 

 the various solutions on such areal or linear increases were very 

 marked and noticeable. Thus strips 30 to 50 mm. in length cut 

 from a single plate when placed in the solutions gave increases in 

 thickness and length as below: 





.01 M. 



O.OOI 



M. 



O.OOOI 



M. 



Th. 



L. 



1 Th. 



L. 



Th. 



L. 



KCl 



1090 p. ct. 



38 p.ct. 



: 800 p. Ct. 1 



33 P- ct. 



1 640 p. ct. 





35 P-ct. 



CaCl 



600 " 



6 M 



1 1350 " 



8 " 



830 " 





10 " 



HC1 



1620 " 



70 " 



1 I600 " 



20 " 



I 925 " 





8 " 



Water 











780 " 





8 " 



The areal increase in the potassium solution varied but little 

 in the different concentrations being much greater than in calcium, 

 which was near that in water. The greatest disproportion how- 

 ever between increase in thickness and in length was in the acid. 



Agar was made into plates with an inclusion of minute pro- 

 portions of chlorides of calcium, potassium and magnesium, which 

 would represent possibilities in the plant cell. When such salted 

 plates were hydrated in solutions of KCl, NaCl and HC1 at 

 0.0001 M the swelling in length amounted to 12 to 14 per cent, as 

 compared with increases of 3 to 4 per cent, which might be shown 

 by pure agar. 



The increase in length of the sections of salted gelatine cut 

 from plates cast to harden heterotropically are as below: 





O.OI 



o.ooi M. 



0.0001 M. 



KCl 



14 per cent. 



14 per cent. 



12 per cent. 



CaCl 



12 " 



*: :: 



12 " 



HC1 



80 " 





8 " 



Among the more important effects it is to be seen that the in- 

 crease in length of heterotropic plates is lessened by the incor- 

 poration of salts when swelled in KCl. The presence of incor- 

 porated salts accelerates increases in length in CaCl 2 in an un- 

 certain manner, but exercises such an effect rising with the con- 

 centration in acid. The presence of incorporated salts lessens the 

 increase in length in KCl, does not modify it greatly in HC1, but 

 exaggerates the increase in CaCU at 0.01 M. 



