1906.] The Chemistry of Globulin. 133 



The value of A attains a minimum between 30° and 50°, probably between 

 30° and 40°. It is worth noticing that this minimum comes near to the 

 temperature of warm-blooded animals. The viscosity of water controls the 

 velocities of an ion at different temperatures and is inversely proportional to 

 them. So the column headed 77EA/C gives relative values of the ratio of 

 EA/C to the velocities of Na and CI at the five temperatures. 



These show a minimum about 40° and can be expressed by 



77EA/C = 45 + 0-031 (£-40) 2 . (3) 



This equation makes the value of A/C at different temperatures depend 

 not only on the viscosity 77, which determines the velocities of the ions, but 

 on specific properties of the globulin, which are a function of the temperature. 

 Certainly one would expect, a priori, that the profound dependence of the 

 chemical and physical properties of proteid on temperature would appear in 

 such an equation ; one would expect the approaching coagulation at 75° to 

 be foreshadowed. It is again striking that the temperature of minimum 

 77EA/C is about 40°, near that of warm-blooded animals. These experiments 

 have yielded in equation (1) the result that the chemical equilibrium 

 between globulin and neutral salts is of a simple type, dependent, as far as 

 the salt is concerned, upon ionic electric charges and velocities, but also 

 dependent upon special properties of globulin. 



It has already been mentioned that KA, KBr, and KI are exceptional to 

 a certain extent and show that other properties of salts than ionic charges 

 and velocities have an influence on their chemical equilibrium with globulin. 

 Moreover, the solvent powers found by Hardy* for globulin from ox blood do 

 not agree closely with those given by Mellanby for horse globulin. For 

 instance, Hardy finds MgS0 4 less powerful than K 2 S0 4 , whereas Mellanby 

 finds its power 8/6 of that of K 2 S0 4 . Hardy finds KN0 3 , NaN0 3 , and 

 NH4NO3 1*5 times as powerful as KC1 and NaCl. Yet Hardy's data on the 

 whole show that valency is the chief factor controlling solvent power. He 

 finds K and NH 4 oxalates to have the same power as (NH 4 ) 2 S0 4 and an 

 equivalent of Na citrate 3*3 times as powerful as NaCI, so the gramme 

 molecule would be 9*9 times as powerful as that of NaCl. On Mellanby's 

 principle it would be (3 2 + 3)/2 or six times as powerful. Further investiga- 

 tion must clear up these points. 



2. Solution of Globulin in Acids and Alkalies. 



Hardy's experiments show that the reactions between globulin on the one 

 hand and acids and alkalies on the other take place under the usual chemical 



* Loc. cit.j pp. 308 and 309. 



