Jacques Loeb. 54 
o 
I II Il 
22.02 em. 52.8 em. 12.9 om. 
The gelatin treated first with m/8 NaCl swelled after removal 
of the salt two and one-half times as much in distilled water as 
did the gelatin not treated previously with NaCl. We are, 
therefore, justified in saying that blocks of gelatin behave in the 
same way as does powdered gelatin if only care is taken that the 
excess of salt is removed from the block before it is exposed to 
the distilled water. If a block of gelatin is first put into M/8 
NaCl and then into distilled water, we get different results on 
account of the slowness of the diffusion of the salt into and out 
of the block. ; 
In experiments with powdered gelatin we had found that the 
valence of the cation was much more effective than the valence 
of the anion. A previous treatment of powdered gelatin with 
M/8 CaCl, (or MgCls or SrCle or BaCl,) did not cause the exces- 
sive swelling which was caused by m/8 NaCl, and it was found 
that the addition of a small amount of CaCl, to NaCl stopped 
the after-effect of NaCl upon the subsequent swelling of gelatin 
in H;O (antagonistic salt action). The same is true for blocks of 
gelatin as the following experiment shows. 
2 gm. of powdered gelatin were put into each of three cylin- 
drical funnels. Funnel I was perfused six times with 25 cc. H20; 
funnel II twice with 25 cc. M/8 CaCl, and then four times with 
25 cc. H:O; and funnel III six times with 25 cc. M/8 CaCle. The 
next day (after all the water had drained off) the weight of the 
gelatin liquefied by heating to about 40° was | 
if Ay III 
27.8 gm. 25.8 gm. 24.3 gm. 
The CaCl, treatment had, therefore, little effect upon the 
swelling of powdered gelatin. The mass of the three lots was 
then reduced by evaporating in a collodion sac to 7.6, 7.1, and 7.3 
gm. each and blocks of (I) 6.2, (II) 6.0, and (III) 4.7 gm. were 
cut out. Blocks I and II were put into distilled water, and 
block III into M/8 CaCl. After 41 hours the weight was as 
follows: 
iE 1 III 
25.4 gm. 24.1 gm. 17.3 gm. 
