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On the Chlorophyll of Living Plant-Cells. [June, 
III. ON THE CHLOROPHYLL OF LIVING 
PLANT-CELLS, AND ON THE ASSIMILATION OF 
CARBON. 
E purpose laying before our readers the results of 
certain investigations which Dr. J. Reinke has 
communicated to the German Botanical Society, 
and which have appeared in its “ Berichte ” (Proceedings), 
as well as in the “ Naturforscher ” and in other foreign 
journals. 
The reduction of the carbonic acid of the air is a function 
of light and of the chlorophyll of living plant-cells. If we 
wish to understand this process — the very foundation of 
vegetable nutrition — we shall find a study of chlorophyll 
in its solutions insufficient. We must instead, or in addi- 
tion, examine the behaviour of chlorophyll with light, whilst 
it exists in the living vegetable cell. The remaining con- 
stituents of the living cell do not appreciably interfere, as 
in a purely green leaf they consist of colourless, transparent 
substances, which absorb light in a manner similar to 
chlorophyll, though less powerfully. In the case of trans- 
mitted light they are therefore inactive, and merely reduce 
the degree of illumination by reflecting and refracting a 
certain portion of the radiations. 
The air which is present in leaves has doubtless a dis- 
turbing influence, on account of its low refractive power. . 
Dr. Reinke expels it from the leaves by means of water, and 
thus obtains very satisfactory results. 
He has determined the absorption-spectrum of the chloro- 
phyll of the living cells in the leaves of numerous phanero- 
gamous plants, by means of a micro-spectroscope. The 
various species show no differences of importance. All agree 
in proving that the absorption-spectrum of chlorophyll as 
contained in the living leaf is always different from that of 
chlorophyll in solution. This result, we must remark, con- 
tradicts the statements of former observers. Dr. Reinke 
gives a drawing of the spectrum of light which has passed 
through living leaves. We notice here two main absorp- 
tions, separated from each other by a minimum which lies 
at the wave-length 550. In the original illustration the 
absorption-spectra of different strata of the leaf are drawn 
one above the other, so that they unite to form a picture of 
the increase of the absorption with the number of the ah- 
