CHLOROPHTLLINE JHROMTJLES. 119 



bands in the first half. When the chromule is abundant it is not 

 difficult to produce the entire chlorophyll spectrum. It is an im- 

 portant fact too, that band I. is visible longer than the bands in the 

 blue. This affords a proof that the chromule retained by the alcohol 

 consists at least in part of normal green chlorophyll matter. Which 

 of the yellow chlorophyll chromules may in addition be also present 

 in the leaf-green — whether etiolin, zanthophyll, or both — can scarcely 

 as yet be determined by spectrum analysis. 



Kraus' statement regarding the glaucous, or gi'ass-green, ingredient 

 is certainly correct. The conclusion which he draws from this is, 

 however, not admissible ; for he supposes that the relatively displaced 

 bands in the blue reveal a special component which he calls Kyano- 

 phyll, and that bands Y., VI., VII., as situated in kyanophyll, together 

 with the similar bands of the yellow alcoholic portion, combine to 

 form the terminal absorption of the normal chlorophyll spectrum. 

 The spectrum from chlorophyll solutions of medium thickness might 

 possibly be thus explained ; but in weaker solutions the three bands 

 of kyanophyll do not present themselves, whereas in equally diluted 

 solutions of kyanophyll they come out distinctly. Apart from this, 

 however, this view is already refuted by the fact that the altered 

 position of bands V., VI., VII., depends on the solvent. 



Kraus was aware of the influence of the solvents, and thought 

 that the displacement of the bands depended on their specific gravity ; 

 but Kundt shows that it depends on their dispersive power. I have 

 found that some solvents of chlorophyll not only cause displacements 

 of the bands, but also remarkable changes in the breadth and intensity 

 of the bands. This would indicate, at least with regard to chloro- 

 phyll, that these solvents have even a chemical influence on the 

 chromule. 



The author next proceeds to a description of the pecu- 

 liarities presented by the spectrum of a solution of chlorophyll in 

 benzol, in which the displacement of bands I., V., VI., and VII., are 

 easily observed, and in addition to this a splitting of band I. first into 

 two and then into three bands is very distinctly to be seen when 

 medium thicknesses of chromule are used. A similar splitting of 

 band I. has already been observed by Schom, Gerland, and Rauwenhoff 

 in ethereal solutions of chlorophyll, and this splitting of band I. may 

 under favourable circumstances be noticed also even in alcoholic 

 solutions. Turpentine chlorophyll also shows this splitting. 



The situation of the bands characteristic of benzole chlorophyll, 

 of course comes out also in the benzole portion of separated chloro- 

 phyll, and constitutes in fact the displacement of the bands in the 

 blue, which Kraus saw and described quite correctly ; but his 

 assumed composition of the chlorophyll spectrum cannot be inferred 

 from this, simply because the bands of his kyanophyll are not present 

 at all in unseparated alcohol-chlorophyll. A further study of these 

 alcoholic and benzole portions will occasionally reveal slight devia- 

 tions in the respective situations of the bands as described by me. 

 These may very easily be explained if we only bear in mind that in 

 most cases of separation we do not obtain pure solutions of chloro- 

 phyll in. this or that solvent, but in a mixture of solvents. By 

 judiciously regulating the relative proportions of the solvents, we 

 may sometimes succeed in producing the observed medium. 



