88 SUMMAEY OF CURRENT RESEARCHES RELATING TO 



acid, along with other substances, a nitrogenous base is produced, 

 identical with the adenin of the larger glandular organs. This 

 substance may be obtained pure in crystals of the composition 

 CgHgNfi, capable of forming various compounds with acids. Adenin 

 belongs to the group of xanthins. The primary products of decom- 

 position of nuclein are probably adenin and guanin, xanthin and 

 hypoxanthin being only secondary products. In conjunction with 

 nuclein adenin appears to play an important part in the physiology 

 of animal and vegetable tissues. 



Chemistry of Chlorophyll.* — Mr. E, Schunck, after separating 

 the phyllocyanin and phylloxanthin of chlorophyll by Fremy's 

 method, investigates the properties of the former substance. It is 

 obtained as a dark-blue crystalline mass resembling indigo. It is 

 decomposed between 160° and 180°. It contains nitrogen, but no 

 sulphur. It is insoluble in water, petroleum-ether, and ligroin, but 

 soluble in alcohol, ether, chloroform, glacial acetic acid, benzol, 

 anilin, and carbon disulphide. The best solvent is chloroform, a 

 minute quantity imparting an intense colour to the solvents. Oxidizing 

 agents decompose it easily, yielding yellow amorphous products, the 

 solutions of which show no absorption-bands. It dissolves easily in 

 concentrated sulphuric, hydrochloric, and hydrobromie acids, yielding 

 dark-blue solutions, which show spectra differing from that of phyllo- 

 cyanin. They are unstable, and water precipitates from them phyllo- 

 cyanin unchanged. It dissolves readily in dilute caustic potash or 

 soda lye; phyllocyanates are precipitated from these solutions by 

 earthy or metallic salts. Phyllocyanin acts the part of a weak base, 

 forming metallic compounds with strong acids. Chlorophyllan is 

 probably an impure substance containing some fatty acid along with 

 phyllocyanin. 



Coloiirless Chlorophyll.t — M. C. Timiriazeff states that when a 

 chlorophyll solution is treated with metallic zinc and an organic acid, 

 it is reduced through the agency of the nascent hydrogen generated 

 in the reaction, the resulting substance being perfectly colourless, 

 and presenting no traces of fluorescence or of the characteristic 

 spectrum of chlorophyll. In contact with air this substance gradually 

 acquires the green colour and optical properties of chlorophyll. 

 M. Timiriazeff considers this to be a confirmation of his previous 

 hypothesis that the green colour of chlorophyll is due to the presence 

 of iron in the state of an FeOFcaOs compound. 



Researches on Chlorophyll. | — Herr A. Tschirch gives the 

 following as the properties and appearances of the derivatives of 

 chlorophyll. 



I. Soluble in alcohol. 



1. Bodies which show the chlorophyllan spectrum; solution 

 brown. 



a. Chlorophyllan, black rosettes of crystals. 



6. Phyllocyanin ic acid, black lamellEe with superficial blue colour. 



* Proc. Koy. Soc, xxxviii. (1885) pp. 336-40. f Nature, xxxii. (1885) p. 342. 

 X Ber. Deutsch. Bot. Gesell. Generalversammlung, 1885, pp. xliii.-liv. 



