136 



Mr. W. Sutherland. 



[July 26, 



contains T35 per cent, of Cu, and by excess of Cu 2*64 per cent. In 1877, 

 Morner prepared a copper albuminate with 1*2 per cent, of Cu, and another 

 with 1*85 per cent. In 1887, Chittenden and Whitehouse obtained copper 

 albuminate containing from 0*71 to 1*21 per cent, of Cu, but found that by 

 redissolving and reprecipitating the percentage could be raised to 2*19. 

 Now with our formula for CuS0 4 , and the fact that Mellanby's globulin 

 solution contained 0'024 gramme of globulin per cubic centimetre, we get 

 0'024 p = 88 c, that is to say, that at the earlier stages of precipitation 

 CuS0 4 throws down 88 times its own weight of globulin. Thus, neglecting 

 the small amount of Cu left in solution, we can calculate that the copper 

 globulinate of Mellanby's experiment contained 0*45 per cent, of Cu. If all 

 the globulin is precipitated, our equations give that 0*55 of the precipitate 

 contains 0*45 per cent, of Cu, and 0'45 of it contains 0*83 per cent, of Cu, so 

 that the precipitate as a whole contains* 0*62 per cent. 



These are only about one-third of Morner and Harnack's values for the 

 albuminates. But the larger value, 0*62 per cent., is close to the smallest of 

 Chittenden and Whitehouse's, namely, 0*71. In the same way, from our 

 equations for Mellanby's ZnS0 4 data, we find that the first precipitate of zinc 

 globulinate contains 06 1 per cent, of Zn, and that if all the globulin is 

 thrown down the compounds average 1*22 per cent, of Zn. Now Chittenden 

 and Whitehouse found 0*91 per cent, of Zn in their zinc albuminate. So 

 there is a fair correspondence between the composition of Mellanby's 

 globulinates and Chittenden and Whitehouse's albuminates of Cu and Zn. 

 Thus it bears upon the present inquiry to look more closely into the 

 albuminates of these investigators. The following table contains, in the first 

 row, the fraction / of metal in unit mass of its albuminate, in the second the 

 equivalent mass E of the metal, and in the third the ratio //E. 



Table IV. 



10V 



Cu. 



Zn. 



Fe. 



U. 



Pb. 



Hg. 



Ag. 



71 

 32 

 22 



91 

 32-5 



28 



95 

 28 

 34 



460 

 120 



38 



250 



104 



24 



289 



100 



29 



409 



108 



38 



E 



10 3 /7E 





Erom the mean value of the last row we find the percentage of heavy 

 metal in its albuminate to be 003 E. Hence the minimum molecular mass 

 for albumin in the albuminates is 100/0*03 or 3300 nearly. Hence, we infer 

 from the above argument that Mellanby's data would agree with the 

 altogether independent data for the albuminates in making the minimum 



