1905] BRIEFER ARTICLES 305 
chlorophyll spectrum in a single leaf, but all leaves give all these bands 
when two or three are used. _The bands in the spectrum of a solution of 
chlorophyll were compared with those in the living leaf in two ways: (1) by 
observing the two spectra at the same time, one with direct light and the 
other by means of the comparison prism; (2) by observing the position 
of the bands in direct sunlight with reference to the Fraunhofer lines. In 
all cases the bands appear in exactly the same place in the spectrum of a 
leaf as in that of a standard solution giving the normal chlorophyll spectrum. 
From the above it is plain that the most typical spectra are yielded by 
those non-acid leaves from which the chlorophyll can be extracted most 
easily, namely (in the order of their excellence) Primula obconica, Raphanus 
sativus, Vicia Faba, Abutilon (young leaf), Avena sativa, Cestrum elegans 
(young leaf), Euphorbia pulcherrima (young leaf), Lycopersicum esculen- 
tum, Primula sinensis, and Ricinus communis. 
Another well-known optical property of chlorophyll is its fluorescence, 
all solutions of chlorophyll being slightly fluorescent. The products of 
the decomposition of chlorophyll, however, seem to be more fluorescent: 
than chlorophyll itself. A solution of chlorophyll extracted with boiling 
alcohol from boiled leaves in the light is more fluorescent than a solution 
of unchanged chlorophyll. Of course some leaves are better than others, 
and of all the leaves in the above table, the very best are Jacobinia mag- 
nijica, Cineraria cruenta (the dark-leaved varieties), Cestrum elegans, and 
Hedera Helix, Standard solutions from these leaves give a brilliant 
Pia fluorescence.—SopHia Eckerson, Smith College, Northampton, 
ass, te, 
FURTHER OBSERVATIONS ON THE STRUCTURE OF THE 
STARCH GRAIN.! 
1S a previous paper (1) on the structure of the starch grain, I showed 
“oO peripheral layer of the potato starch grain breaks and recurves 
cement with certain reagents, much like the cutin layer of an epidermal 
"Uh on treatment with sulfuric acid. While I had previously observed 
ay aia gue layer is stained with certain of the aniline dyes, I 
Protoplas . me effect might probably be due to the remains of plastids or 
I ie mic material, rather than to the presence of a distinct membrane. 
eral atte satisfied, however, that it can be demonstrated that the periph- 
It of the starch grain is a distinct membrane. : 
's well known that upon the addition of an iodin solution to unaltered 
1 R f : : 
ber a dat the meeting of the Society for Plant Morphology and Physiology, Decem 
