186 Dr. S. J. Lewis. Ultra- Violet Absorption Spectra and 



Chick considers the two globulins to be the one a modification of the other.* 

 The results of the present inquiry may, on the whole, be held to support this 

 view, but they do certainly indicate also that there is some important 

 difference between them, which is borne out by the two following con- 

 siderations : — 



(a) The amplitude figure is much greater for the pseudo-globulin than it is 

 for the eu-globulin. 



For pseudo-globulin this figure is 072 for both horse and human ; for 

 eu-globulin it is 053 for horse and 066 for human. Therefore, with both 

 varieties, there is a marked difference between the two globulins. 



Also, for both horse and human proteins, the curve for pseudo-globulin is 

 very slightly broader than that for eu-globulin ; this is so for the human 

 more than for the horse. 



(b) The intensity of the selective absorption is much greater for the 

 eu-globulin than it is for the pseudo-globulin, as shown by the magnitudes of 

 the extinction coefficients. 



For horse, the figures for eu-globulin are 1"42 for the head and - 89 for the 

 foot, mean 1'16, against those for pseudo-globulin, which are 1"19 for the 

 head and - 47 for the foot, mean 083, giving an excess in favour of 

 the eu-globulin of 033, or 39 per cent. 



For human, the corresponding figures for eu-globulin are 1*51 for the head 

 and 085 for the foot, mean T18, against those for pseudo-globulin, which 

 are l - 35 for the head and 063 for the foot, mean 099, giving an excess in 

 favour of the eu-giobulin of 019, or 19 per cent. 



In passing, it may be observed that both horse and human pseudo- 

 globulin exbibit the same amplitude in the band, namely, 072, and that the 

 bands for both horse and human eu-globulin have nearly the same mean 

 values for the extinction coefficient, namely, T16 and 1'18. 



Although the problem is not yet solved, it may be said that the spectro- 

 scopic phenomena are in harmony with the view expressed by Dr. Chick, 

 that eu-globulin is a protein-lipoid complex resulting from the interaction of 

 pseudo-globulin with a minute proportion of a lecithin. 



Observations on the Figures for Albumin, Tables V and VI. 



The extinction coefficients of albumin contrast strongly with those for 

 either of the two globulins. The amplitude value is only 036 for the horse 

 or 023 for the human, instead of about 07, which was found for the two 

 globulins. 



* ' Biochem. Journ.,' vol. 8, pp. 404-420 (1914). 



