132 



Mr. W. Sutherland. 



[July 26, 



centration required just to dissolve the whole of a given globulin suspension. 

 From Mellanby's graphs we find this concentration C to be 0'000094 E for 

 salts of the type NaCI, E being the gramme equivalent. Eor the type CaCl 2 

 and Na 2 S0 4 it is 0*000065 E and for MgS0 4 0*000056 E. Hence, for 1/C 

 for these three types, we get the values 10600/E, 15400/E, and 17850/E. 

 If we use gramme molecular mass M instead of gramme equivalent E, these 

 become 10600/M, 30800/M, and 35700/M, in which the numbers are as 

 2:6:7, corresponding to the ratios 2:6:8 found by Mellanby when using 

 average solvent powers. We can regard this result in a different way. Let 

 us write (1) in the form 



p(l-£)=£c(l-p), (2) 



and study A/C for each type, thus making the absolute concentration a 

 prominent. The values of A/C for the three types are 6400/M, 18800/M, 

 and 23600/M, the numerical parts of which are MA/C, and are more nearly 

 as 2 : 6 : 8. From this point of view, we find Mellanby's law apply better to 

 MA/C than to M/C, to an average value of which Mellanby applied it. In 

 Section 4, I shall try to give a theoretical explanation of Mellanby's law 

 applied to MA/C. Meanwhile, to complete the discussion of experiments 

 bearing on A, we shall consider his results concerning the influence of 

 temperature on the solvent power of XaCl for globulin. He comes to the 

 conclusion that the solvent power is proportional to the electric conductivity 

 or summed ionic velocities of the solution of NaCI at the temperatures 

 used. But it will be better to investigate the effect of temperature on A and 

 A/C, and then follow Mellanby in taking account of ionic velocities in this 

 connection. 



The following table contains the values of A which I have calculated from 

 Mellanby's data* at the five temperatures, also the values of C/E derived 

 from his graphs. The values of EA/C are also tabulated to give relative- 

 values of A/C. The column marked r) gives the viscosity of water at the 

 five temperatures, and the last column rjEAJC : — 



Table II. 



Temp. 



lCA. 



10 6 C/E. 



EA/C. 



10*T}. 



»?EA/C. 



°0. 













1-5 



860 



168 



5120 



172 



88 



20 



600 



102 



5860 



101 



59 



30 



536 



84 



6310 



80 



50 



40 



512 



75 



6790 



66 



45 



50 



605 



715 



8470 



55 



47 



* Loc. cit.j p. 353. 



