(as 
INFLUENCE OF ABSORBENT MEDIA ON CHLOROPHYLL. 
The action of sunlight on the chlorophyll within the cell is not 
materially modified if the light passes first through layers of cells 
that do not contain chlorophyll, such as those of the red colored cab- 
bage leaf, since in those cells, as in yellow cells and others, the radia- 
tion that is absorbed is not to any extent that special radiation which 
the chlorophyll absorbs. The absorption of light by the yellow 
cells of the yellow leaves of an alder bush was examined by T. W. 
Engelmann (Agr. Sci., Vol. II, p. 189), who found that these ab- 
sorbed most from the middle of the spectrum and least at either end, 
whereas the chlorophyll absorption is complementary to this. He 
also found that the green leaves of the alder bush, when expesed to 
the light side by side with the yellow leaves, set free far more oxygen 
than these, so that it seems probable that if the yellow cells con- 
tain only pure xanthopyll there assimilating power would be zero. 
INFLUENCE ON THE SUPPLY OF SAP. 
The action of sunshine in producing or altering the colors cf fruits, 
especially the black Hamburg grape, has been experimentally studied 
by Laurent. (Agr. Sci., Vol. IV, p. 147.) Bunches of immature 
grapes quite shielded from the sunlight ripened, colored, and flavored 
as usual, but bunches whose food supply had been cut off by ringing 
the base of the stock supporting the bunch, and then also kept in the 
dark, remained green, small, and sour. Bunches that had been sub- 
jected to the ringing process, but which were exposed to the sunlight, 
produced berries of normal size, some reddish and others green and 
of an acid flavor. He concludes that the coloring matter of grapes 
may be formed in the absence of sunshine, provided a suflicient. sup- 
ply of nourishment be at hand, but if this supply be arrested then the 
color remains imperfect. 
CLIMATE AND THE LOCATION OF CHLOROPHYLL CELLS. 
Guntz (1886) has studied the anatomical structure of the leaves of 
cereals and grasses in their relations to locality and climate. This 
connection is infinitely complex. Among other items brought out by 
him we note that the green assimilating organism consists of many 
cells of various shapes and in most cases fills the spaces between the 
nerves of the leaves; in tropical grasses the green cells occur most 
in the inclosing sheath, but in the grasses of the steppes it lies on 
either side of the grooves or ridges. The intercellular gaps, according 
as they are larger or smaller, indicate a moist or a dry soil and, 
equally so, a moist or dry atmosphere. The bast in the leaves of the 
erasses serves primarily to strengthen the whole structure, but the 
bast increases with the dryness of the locality, and its proportional 
distribution is an appropriate, indirect indication of the climate. 
