Contributions to the Chemistry of Chlorophyll. 453 



been added, deposits on cooling and standing a quantity of crystalline 

 needles arranged in pretty rosettes which, after filtering off and dry- 

 ing, appear blnish-green by reflected as well as by transmitted light, 

 and show no metallic lustre ; the alcoholic solution of this compound 

 shows the same absorption spectrum as that of. the corresponding 

 phyllocyanin compound, and, like the latter, it is not decomposed nor in 

 any way changed by treatment with boiling hydrochloric acid. Similar 

 compounds containing iron and silver may be obtained, but their 

 properties are not sufficiently interesting to merit detailed descrip- 

 tion ; they resemble the corresponding phyllocyanin compounds. 



On adding metallic tin to a solution of phyllotaonin in hydro- 

 chloric acid and allowing to stand, the solution soon loses its bright 

 bluish-green colour, and becomes olive-green, finally reddish-yellow. 

 Water now gives a red precipitate, which filtered off and washed 

 dissolves in alcohol with a crimson colour, the solution showing a 

 spectrum similar to that of the final product of the action of tin and 

 hydrochloric acid on phyllocyanin. 



Though there can be little doubt as to the purple crystals formed by 

 the action of hydrochloric acid on an alcoholic solution of alkaline 

 chlorophyll being an ether, I have not succeeded in reproducing it by 

 the direct action of acid on an alcoholic solution of phyllotaonin. 

 The solution retains its bluish-green colour unchanged, deposits no 

 crystals even on long standing, and gives with water a precipitate 

 consisting of uncombined phyllotaonin. A compound resembling that 

 in the purple crystals may, however, be formed from phyllotaonin by 

 a different process. If to an alcoholic solution of phyllotaonin ethyl 

 iodide and a little caustic potash be added, the solution on boiling 

 deposits a small quantity of a black powder, which being collected on 

 a filter and treated with dilute acid, is found to be soluble in alcohol, 

 ether, and chloroform, giving purple solutions which show the same 

 spectrum as solutions of the purple crystals. It is, however, easily 

 soluble in aqueous alkali, and may therefore be a mono-ethyl, the 

 other being a di- ethyl ether. It is probably identical with the com- 

 pound formed directly from phyllocyanin by a similar process, as 

 described in the first part of this memoir, in the solutions of which 

 the spectrum (fig. 13) so frequently referred to was first observed. 

 This very peculiar spectrum belongs, it appears, to four distinct 

 compounds. 



In order to explain the formation of the purple crystals by the 

 process above described, we may suppose that by the influence of 

 alkalis chlorophyll is first converted into a substance which by decom- 

 position with acids yields phyllotaonin, and this in the nascent state 

 and in contact with alcohol and hydrochloric acid undergoes etheri- 

 fi cat ion. 



Of the compounds above described I have analysed such as were 



