Jacques Loeb 043 
der with Ca should not increase the alkalinity of the distilled 
water. This is actually found to be the case by Dr. Dernby 
(Table VI). 
TABLE VI. 
| Hydrogen ion concentration of a solution containing pig’s bladder treated as 
stated (expressed with Sérensen’s symbol pH). 
After 
‘ In M/8 CaCl 1 hr. 
Control zeta 
distilled water, | then in distilled m/8 MgClz m/8 SrCle 
tage IRR RSG eS Oo Sea Re a 
0 6.4 
3° 6.4 
1 About 6.5 6.4 
Then transferred into distilled water; imme- 
diately after transferring the H ion con- 
centration was in all cases the same pH =6.2 
to 6.4. 
3 6.7 6.4 6.5 6.5 
5 7.0 6.6 6.7 Gah 
24 eae 6.9 6.9 6.9 
It is obvious that pig’s bladder previously treated with solu- 
tions of MgCly, CaClz, and SrCl, does not cause a change of the 
same order in the reaction of the water as was found for bladder 
treated with NaCl and NH,Cl. This harmonizes with the as- 
sumption that the bivalent metals form non-dissociable or less 
dissociable gelatin salts. 
IV. 
In the previous note’ the writer has stated that the additional 
swelling caused by a treatment with NaCl was observed in pow- 
dered gelatin and in pig’s bladder, but not in solid blocks of | 
gelatin. It was found that the cause of this difference is the fact 
that it is easy to ionize large masses of powdered gelatin with a 
salt, and then wash the unnecessary salt solution away, while this 
is difficult if not impossible with solid blocks of gelatin. The 
salt solution apparently diffuses slowly in and out of the block. 
For this reason the following modification of the method was 
adopted. Powdered gelatin was treated with a m/8 NaCl solu- 
