682 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The erythrophyll of Bougarel is identical with the chrysophyll of 

 Hartsen. It is not an accompaniment, but a product of decomposition 

 of chlorophyll. It is produced in the cells of plants by the action of 

 dilute acids. Etiolin, the chlorophor of Bohm, the leucophyll of 

 Sachs, belongs also to the chlorophyll-group. A solution of etiolin 

 is oxidized by long standing or the addition of dilute acids. Pounded 

 zinc reproduces pure etiolin. 



The pure colouring matter of chlorophyll can be produced in two 

 ways : — (1) by reducing by means of pounded zinc chlorophyllan, 

 which can readily be obtained pure in crystals ; (2) by treating a 

 concentrated alcoholic solution of chlorophyll with barium chloride, 

 chlorophyll being insoluble in concentrated solutions of salts. 



Tschirch contests the view of Meyer that the protoplasmic en- 

 velope surrounding the chlorophyll-grains is a result of the mode of 

 treatment in their preparation. By experiments on living cells of 

 Elodea and Nitella he supports tlie view that all chlorophyll-bodies 

 and aleurone-grains are surrounded by such an envelope. 



Chlorophyll and the Distribution of Energy in the Solar 

 Spectrum.* — C. Timiriazeff, in a previous communication, showed the 

 intimate relation existing between the absorption of light by chloro- 

 phyll and the intensity of the chemical action produced, and expressed 

 the opinion that this action is dependent on the energy, as measured 

 by its thermal effect, of the rays absorbed. He now calls attention 

 to the fact that Langley's measurements with the bolometer justify 

 this opinion, and prove that the point of maximum energy in the solar 

 spectrum corresponds with the characteristic chlorophyll-band between 

 B and C. The author is now engaged on researches on the quajitita- 

 tive relation between solar energy absorbed by the chlorophyll of 

 leaves and that stored up in the chemical work performed. He finds 

 that, under the most favourable conditions, a plant utilizes 40 per cent. 

 of the energy absorbed. 



Crystalline Secondary Pigments of Chlorophyll.t — J. Borodin 

 finds it very easy, by treating the parts cut up very fine with alcohol, 

 to separate from true chlorophyll several other pigments which always 

 or commonly accompany it. On crystallizing out the alcoholic 

 solution, a great quantity of crystals of various colours appear. The 

 author gives a long list of species on which his experiments were 

 made, in all of which crystallizable substances were found accom- 

 panying the chlorophyll. Spirogyra is a very favourable object. 

 These various substances agree in their insolubility in cold or hot 

 water, and ready solubility in ether, chloroform, and carbon bisul- 

 phide ; they display great resistance to both alkalies and acids. In 

 other chemical properties they manifest great differences, but they are 

 all rendered blue by concentrated sulphuric acid. They may be 

 divided into two groups, those which are most soluble in benzin, and 

 those which are most soluble in alcohol. The latter are also more 



* Comptes Rendus, xcvi. (1882) pp 375-G. Journ. Chein. Soc. Abstr., xliv. 

 (1883) p. G97. 



t Bull. Acad. Sci. Imp. St. Petersbouig, xxviii. (1883) pp. .328-50. 



