88 SUMMARY OF CURRENT RESEARCHES RELATING TO 



xauthophyll, Hanson's clilorophyll-ydlow. The soap, deprived of this 

 yellow i)igmcnt, is now extracted with alcohol-ether, and the pigment 

 thus extracted, not yet quite pure, i>urifietl and crystallized by repeated 

 solution in alcohol-ether. It crystallizes in sphero-crystals. The 

 composition of this substance, resulting from two analyses, was as 

 follows :-C 67 •2G-G7- 91, H 10 -63-10 -30, 16 -97-16 -12, N 5-12- 

 5-55 per cent. 



Chlorophyll-green, as Hansen calls the substance thus obtained, 

 is a black-green powder, easily soluble in dilute alcohol and water, 

 moderately easily in alcohol-ether, chloroform, and fixed oils ; with 

 dilBiculty in pure ether, absolute alcohol and acetic ether ; insoluble 

 in petroleum-ether and bisulphide of carbon. It dissolves in concen- 

 trated sulphuric acid with a green colour ; concentrated hydrochloric 

 acid produces a green substance insoluble in ether ; nitric acid dis- 

 solves it with a light red colour ; nascent hydrogen bleaches its solu- 

 tion ; solution of silver is energetically reduced by it. The aqueous 

 solution of chlorophyll-green is very susceptible to light, as also is that 

 in chloroform ; a solution in ether is more persistent, one in alcohol 

 still more so. The spectrum of a solution shows the four bands of 

 the alcoholic extract of chlorophyll, but somewhat displaced towards 

 the blue end of the spectrum. 



The chlorophyll-yellow, which is separated from chlorophyll- 

 green by petroleum-ether, crystallizes in dark yellow needles. The 

 solutions are not fluorescent ; the absorption spectrum has only three 

 bands in the blue half, none in the red. It is soluble in alcohol- 

 ether, petroleum-ether, and chloroform. Tlie quantity of chlorophyll- 

 yellow present in green leaves, as compared with that of chlorophyll- 

 green, is only about 1 per cent. 



Fluorescence of Chlorophyll in Leaves.* — J. Eeinke corrects his 

 previous statement tliat the chluruphyll of living leaves does not 

 fluoresce. In the thick leaves of Ficus clasiica he finds a certain 

 amount of fluorescence, though very feeble compared to that of an 

 alcoholic solution of chlorophyll. 



Morphology of Chlorophyll - grains.! — A. Tschirch repeats 

 evidence in favour of his view — as opposed to that of F. Schmitz — 

 that every grain of chlorophyll is surrounded by its own membrane 

 of protoplasm, the colouring matter of two ditFerent grains never 

 actually being in contact. He also reaffirms the statement that every 

 grain of chlorophyll is composed of a colourless matrix or frame- 

 work, the spaces between the meshes of this being filled uj) by the 

 colouring substance. 



Formation of Gum in Wood, t — B. Frank has examined the 

 mode of formation and the physiological significance of gum in a 

 number of exogenous trees, mostly belonging to the Leguminosse and 

 Amygdaleae. It is the universal product of special conditions, and 



♦ Ber. Deutsch. Bot. Gesell., ii. (1884) pp. 265-8. 



t Gesell. Naturf. Freunde Berlin, May 20, 18&4. See Bot. Centralbl., xix. 

 (1884) p. 254. Cf. this Journal, iii. (1883) p. 688 ; iv. (1884) p. 920. 

 X Ber. Deuttch. Bot. Gesell., ii. (1884) pp. 321-32. 



