JACQUES LOEB 105 



with those for gelatin chloride, phosphate, etc. These curves are 

 interesting in connection with Pauli's statement that trichloracetic 

 acid causes the same low values of viscosity as sulfuric acid. This was 

 the case neither in our experiments on the osmotic pressure nor in 

 those on the viscosity of gelatin solutions. 



Fig. 13 gives the cc. of 0.1 n NaOH, KOH, Ca(0H)2, and Ba(0H)2 

 required to bring 1 gm. of originally isoelectric gelatin in 100 cc. solu- 

 tion to a given pH. One curve suffices for the four alkahes thus prov- 

 ing that Ca and Ba combine with gelatin as bivalent ions. We should 

 expect the curve for the viscosity of Ca gelatinate to be considerably 

 lower than that of Na gelatinate. Fig. 14 shows that this is true. 



SUMMARY. 



1. This paper contains experiments on the influence of acids and 

 alkalies on the osmotic pressure of solutions of crystalline egg albu- 

 min and of gelatin, and on the viscosity of solutions of gelatin. 



2. It was found in all cases that there is no difference in the effects 

 of HCl, HBr, HNO3, acetic, mono-, di-, and trichloracetic, succinic, 

 tartaric, dtric, and phosphoric acids upon these physical properties 

 when the solutions of the protein with these different acids have the 

 same pH and the same concentration of originally isoelectric protein. 



3. It was possible to show that in all the protein-acid salts named 

 the anion in combination with the protein is monovalent. 



4. The strong dibasic acid H2SO4 forms protein-acid salts with a 

 divalent anion SO4 and the solutions of protein sulfate have an 

 osmotic pressure and a viscosity of only half or less than that of a pro- 

 tein chloride solution of the same pH and the same concentration of 

 originally isoelectric protein. Oxalic acid behaves essentially like a 

 weak dibasic acid though it seems that a small part of the acid com- 

 bines with the protein in the form of divalent anions. 



5. It was found that the osmotic pressure and viscosity of solutions 

 of Li, Na, K, and NH4 salts of a protein are the same at the same 

 pH and the same concentration of originally isoelectric protein. 



6. Ca(0H)2 and Ba(0H)2 form salts with proteins in which the 

 cation is divalent and the osmotic pressure and viscosity of solutions 

 of these two metal proteinates are only one-half or less than half of 



