534 Proteins 
25 cc. of a definite NaCl solution lower than M/8 NaCl; namely, 
M/16, M/32, m/64, M/128, etc., down to m/2048 or lower. It is 
found that after three perfusions the additional swelling of the 
gelatin becomes noticeable in the funnel which has been washed 
with M/64 or less concentrated NaCl solution and that the ad- 
ditional swelling increases rapidly with the diminution of the 
concentration of the NaCl solution. The explanation is that 
concentrations of NaCl above m/64 suppress the electrolytic dis- 
sociation of the gelatin-NaCl compound to such an extent that the 
swelling will not exceed that caused when the gelatin is perfused 
permanently with m/8 NaCl. Concentrations of m/64 and be- 
low no longer suppress the ionization of the gelatin salt com- 
pletely and the suppression is the smaller the greater the dilution 
of the NaCl used for perfusion. Hence the swelling of the gelatin 
increases rapidly with the dilution of the NaCl solution below 
mM/64 and reaches a maximum when distilled water is used for the 
perfusion. Table II gives adequate examples. This fact had 
already been published.® 
2. The second proof consists of the fact that when the gelatin 
powder is first perfused with mM/8 NaCl and then with a solution 
of a non-electrolyte, the increasing dilution of the non-electrolyte 
is without effect. Table I illustrates this statement. The table 
gives the result of four sets of experiments. In each set about 
fourteen cylindrical funnels contained 2 gm. of powdered gelatin 
and each funnel was perfused twice with 25 cc. M/8 NaCl. After 
this the various funnels of one series were perfused with solutions 
of either NaCl or glycerol or cane sugar or ethyl, alcohol of in- 
creasing dilutions. The swelling was measured after three per- 
fusions. In order to allow all the liquid not held by the gelatin 
(or by adhesion) to filter out the final measurement was taken - 
after 24 hours. Precautions were taken to avoid error by evap- 
oration. Since the cross-section of all the cylindrical funnels 
was the same the increase in the height of the cylindrical mass of 
gelatin above the height of the mass reached by the perfusion 
with mu/8 NaCl may serve as a measure of the additional swelling. 
The difference between the influence of the electrolyte and the 
non-electrolyte is very striking. Gelatin treated with m/8 NaCl 
does not show any further swelling when treated with m/8 or 
M/16 NaCl; from m/64 on the swelling begins, gradually increas- 
