448 Effect of Electrolytes. I] 
This experiment is of particular interest from the biolegical 
point of view, since Loeb® has found that the effectiveness of 
cations in hindering the penetration of acetic acid into the egg of 
Fundulus increases with the valence, and this result is contrary 
to the suggestion that antagonism is due to oppositely charged 
ions. While this result cannot be paralleled in gelatin by the 
alcohol method, the experiment recorded in Fig. 5 shows with- 
out a doubt that antagonism between acids and salts with biva- 
CC. ALC. TO PPT. 
25 4 ACETIC ACID .074 M 
.037 M 
64) wf oe ee ee 
4 H20 
ft 
NaOH .015 M 
5 
0 | ws | 4M 
CaClo == =a 
Fig. 4. Curves showing the effect of CaCl, on the alcohol number of 
gelatin plus NaOH and acetic acid. CaCl, is antagonistic to NaOH but 
not antagonistic to acetic acid. (See Table IV.) 
lent cations is possible in gelatin. The writer has also found 
that CaCl 1.5 m will antagonize HNO; and AICI; in the same way. 
Fischer’ has found, in studying the swelling of gelatin in acids, 
that the effectiveness of cations in hindering this swelling in- 
creases with the valence of the cation. Thus he found that 
FeCl; hinders swelling in HCl more than CaCl. This is in ac- 
cord with Loeb’s results but is the reverse of the evidence so far 
obtainable by the alcohol method, where no indication of antag- 
onism between HCl and AIC]; has as yet been found. As it is 
impossible to follow the effects of ‘HCl and AlCl; by this method, 
15 Loeb, J. Biol. Chem., 1916, xxvii, 365. 
16 Fischer, (idema and N ephritis, New York, 2nd aiition: 1915. 
