222 BOTANICAL GAZETTE [MARCH 
There is at the present time one international publication devoted 
entirely to cecidology, Marcellia, now in its eighth volume, edited by Dr. A. 
Trotter, Avellino, Italy, which publishes original papers and also current 
bibliography.— Met. T. Coox, Delaware Agric. Exper. Station, Newark. 
FIXING AND STAINING TANNIN IN PLANT TISSUES WITH 
NITROUS ETHERS 
(WITH EIGHT FIGURES) 
Immature dates exposed to the vapor of amyl or ethyl nitrite to stimu- 
late premature ripening were observed to turn dark brown very rapidly. 
This was found to result from the staining of the giant tannin cells which 
occur near the cuticle. After several hours’ exposure, hard tannin grains 
were formed in the tannin cells of green dates and persimmons, which had 
the same physical char- 
acters as the grains oc- 
curring naturally in ripe 
fruit; they could be 
separated quite pure by 
gravity in water, and 
when pressed beneath 
the cover glass fractured 
like grains of gelatin. 
The juice of the up- 
ripe date gives a dense 
brown precipitate with 
ethyl or amyl nitrite oF 
with sodium nitrite and 
free acid. Persimmon 
juice gives an intense 
deep wine-red color, 
but no precipitate. 
Tannic and gallic acids 
give yellow, while phloroglucin and some other higher phenols give 
a red color very similar to that given by date or persimmon juice. 
Phloroglucin also gives a precipitate, but it does not correspond in appear 
ance with that given by date juice. The other higher phenols also give 
yellow or red color reactions with nitrous ether. The gummy matter, 
pectin, etc., precipitated from the juice by alcohol carries with it much of 
the substance that reacts with the nitrite, and the color given by this pre 
Fic. t.—Japanese persimmon. 
