340 
On the Chlorophyll of Living Plant-Cells, [June, 
a recent alcoholic extract was dissolved in melting paraffin, 
and displayed the same intense fluorescence as in the alco- 
holic solution. On allowing the paraffin to cool, when it 
congealed to a transparent cylinder of a uniform green 
colour, it did not possess the slightest fluorescence, which, 
however, returned on melting the paraffin. Hence it would 
follow that chlorophyll is present in plants in the solid con- 
dition, and not in solution. 
The colour in which leaves appear to us is green. The 
light reflected by leaves consists, as both Reinke and Lom- 
mel have found, of the same radiations which have passed 
through a single leaf, — i.e., the extreme red nearly as far as 
B, and the rays between C and E, in moderate intensity, 
whilst the dark green and blue are only faint. A spectro- 
scopic examination of the sunlight reflected from illuminated 
leaves shows the absorption-speCtrum of chlorophyll very 
distinctly. That a light which consists of red, 720 — 700, 
and green, 540 — 520, should appear to us green is explained 
by Reinke by the consideration that our retina is much less 
sensitive to red than to green, and whence the former is less 
prominent in the general sensation. 
These remarks on the light reflected by foliage and grass 
may, perhaps, explain an anomaly in the sphere of art. 
Landscape-painters generally find the green of trees and 
fields a very difficult colour to reproduce to their satisfaction. 
Again, we admire the effects produced in Nature when blue 
flowers — such as the wood-hyacinth, the harebell, the gen- 
tian, or the forget-me-not — appear in close juxtaposition 
with the green of leaves. Yet we find that in the decorative 
arts it is not easy to combine blue and green advantageously. 
We may now see the reason for these anomalies. Our green 
dyes and pigments differ widely in their optical composition 
from chlorophyll. 
Dr. Reinke, in passing to the important question of the 
relation of living chlorophyll to the assimilative process, 
points out that the colour — i.e., the impression which the 
leaf of a plant makes upon our eyes — bears no relation to 
the reduction of carbonic acid. On the contrary, we have 
here to consider exclusively those luminous undulations 
which are absorbed by the leaf, since only light which is 
absorbed can be transformed into any other form of energy 
within the absorbing body. Earlier observers have not 
overlooked this point. Thus Dr. Lommel concludes that the 
maximum of the reduction of carbonic acid, and the absorp- 
tion of carbon, coincides with the absorption-maximum 1. 
of the spedtrum of chlorophyll. He conceives that each 
