JACQUES LOEB 



375 



cess in the gelatin treated with m/128 and m/64 HBr. Corre- 

 sponding abnormal values are found in the curves for conductivity, 

 osmotic pressure, and swelling. The same is shown in Fig. 8. It 



Region of QelJtin-Br 



(soelectnc 

 point Reislon of Gelatin 



60 

 70 

 60 

 50 

 40 

 30 

 20 

 10 





 175 

 150 

 IZ5 

 100 

 75- 

 50- 

 25 







5 



4 



3 



2 





pH 



1 c2 M iH * 

 40 ^^ 4.Z « 43'^'4.6*''43 il M 55 55 55 56 



Fig. 7. Same curves as in preceding figures except that gelatin, after the 

 acid treatment, had been washed four times with H2O. Explanation as in pre- 

 ceding figures. Notice that curves are parallel and the gelatin is free from Br 

 for pH > 4.7. 



is, therefore, the Br number which determines the curves, i.e. the 

 amount of gelatin bromide formed. Fig. 8 gives the curves for eight 

 washings. Again the parallelism between the curves for the Br num- 

 ber and the other physical properties is obvious. 



