1895.] Contributions to the Chemistry of Chlorophyll. 321 



I and II appear more clearly defined in consequence of the clearing 

 up of the space between them, while band III is shifted nearer the 

 blue end and becomes paler, band IV, on the other hand, becoming 

 much darker. After the solution has stood for a few days a fifth 

 band nearer the blue end, and equal in intensity to the fourth, appears. 

 The same changes take place, but more slowly, when tartaric acid is 

 employed in place of hydrochloric acid. When acetic acid, however, 

 is taken, the solution remains unchanged for some time ; it then 

 becomes yellowish-green and shows four bands as before, but the fifth 

 band never makes its appearance however much the action may be 

 prolonged. These changes in the spectrum of chlorophyll solutions 

 on the addition of various acids may be explained by supposing that 

 phylloxanthin is formed in the first instance, and is then, by the 

 continued action of the acid, converted into phyllocyanin. The 

 conversion though slow, on the whole proceeds more rapidly at the 

 commencement than towards the end of the process, and is evidently 

 due to hydrolysis. Similar phenomena are observed in the case of 

 melitose, the metamorphosis of which also passes through two stages, 

 being first converted by the action of emulsin into melibiose, which 

 then by hydrolysis with acid yields galactose and fructose. 



The phylloxanthiu employed in the experiments about to be 

 described was obtained in accordance with the directions given in 

 the fourth memoir of this series, We have nothing to add to the 

 account there given of the properties of phylloxanthin, except that 

 when quite pure its solutions show only four absorption bands, not 

 five as there stated, a fifth band, when it appears, indicating the 

 presence of phyllocyanin. 



Into an ethereal solution of phylloxanthin free from phyllocyanin, 

 a current of dry hydrochloric acid gas was passed, the solution being 

 kept cool, until quite saturated, and it was then shaken up with 

 concentrated hydrochloric acid. The latter gradually acquired a 

 bluish-green colour, which became darker on standing. The two 

 liquids having remained in contact for some time were separated, and 

 the lower acid one was mixed with several times its volume of water, 

 which gave an almost black flocculent precipitate, The whole was 

 then shaken up with ether, in which the precipitate dissolved, yielding 

 a solution which, after washing with water, showed the olive-green 

 colour peculiar to solutions of phyllocyanin as well as the five 

 absorption bands belonging to the latter in their usual position and 

 with their usual relative intensities. That a formation ot phyllocy- 

 anin had actually taken place was proved by the following experi- 

 ments. The ethereal solution of the product obtained was evaporated. 

 Part of the residue left was dissolved in caustic soda ; the solution, 

 after standing for some time, was supersaturated with acetic acid, 

 and then shaken up with ether ; the ethereal solution was evaporated, 



