66 BOTANICAL GAZETTE [jULY 
change of the yellow-brown (which the author compares to the color of living 
diatoms) to green follows immediately upon heating to the boiling point or by 
the addition of water, and somewhat less quickly upon the addition of alcohol, 
ether, or glycerin. 
Chlorophyll bodies killed by boiling water, by drying, or by any medium 
which does not destroy the coloring matter, show this reaction likewise. Solid 
chlorophyll prepared from an alcoholic extract also shows it. Alkali- 
chlorophyll does not; which confirms the contention of Tschirch, Schunck, 
an archlewski, as against A. Hansen, that dilute alkalies do alter 
chlorophyll. 
Diatoms and brown alge, after being killed by boiling water, upon which 
they become green, show the reaction, but in Floridee and Cyanophycee its 
value is impaired by the accompanying reactions of phycoerythrin and phy- 
cocyanin. 
No other bodies have been found by Molisch to respond to the chlorophyll 
test—_C. R. B. . 
Mo iscu also gives an account” of the crystallization of xanthophyll and 
his method of recognizing this yellow coloring matter which always accompa 
nies chlorophyll. Inasmuch as the two are separable in solution, it seem 
possible to devise a mode of removing the chlorophyll and leaving the xal 
thophyll zx the leaf. The process is as follows: Fresh green leaves or small 
pieces of them are brought into 40 per cent. (by volume) alcohol which contains 
20 per cent (by weight) of KOH. In this they remain several days protected 
from light, until all the chlorophyll is extracted. To prevent absorption of 
CO, this should be done in glass preparation jars with close-fitting glass StP" 
pers. The potash solution is then washed out for several hours with distilled 
water and permanent preparations made by mounting bits of the leaves in 
pure glycerin. The xanthophyll is found crystallized in almost every pre- 
viously chlorophyllous cell. | 
- This process has yielded the described result in about 100 genera of seed 
plants at different times of year. Only rarely does the xanthophyll remain 
as yellow drops or diffused in the cell sap. _ 
After giving an account of the physical and chemical peculiarities of the 
crystals Molisch points out the close similarity of the yellow coloring matters; a 
xanthophyll, chrysophyll, etiolin, phycoxanthin, etc., and their relation t0 a 
carotin. He proposes the use of the word carotin in the broad sense, already a 
given to it by Zimmerman,” to designate all the yellow and orange-red CTy> 4 
tals of the leaf obtained by the method described. It would therefore desig: — a 
nate not a chemical individual but a group of nearly allied substances, jut 2 
as ‘‘sugar’’ and “albumen” do.—C. R. B. 
*° Berichte d. deutsch. bot. Gesells. 14:18. 1896. 
** Bot. Mikrotechnik 99. 
