98 BULLETIN OF THE BUSSEY INSTITUTION. 
No. 8.— Experiments made to test the question whether 
mannite can be regarded in any large and general way 
as serving as reserve food in flowering plants. By F. H. 
SrorER, Professor of Agricultural Chemistry. 
For more than one hundred years chemists have occasionally 
detected the presence of mannite in a variety of phanerogams, 
though the discovery that this substance is apt to be formed 
through the hydrogenation of sugars in several different kinds of 
fermentations — notably the viscous, the lactic, and the butyric 
fermentations — has in several instances cast doubts as to whether 
the observed mannite really existed, as such, in the living plants 
whose parts were subjected to chemical examination. Gayon 
and Dubourg * have described a special ferment which changes 
levulose to mannite; and Mazé and Perriert have found that a 
ferment in sour wine has similar properties. In presence of 
levulose this ferment causes mannite to be formed by the action 
of hydrogen liberated from water. Laborde { also has shown that 
the ferments which cause wine to ‘‘ turn” are analogous to the 
mannitic ferment of Gayon and Dubourg. On experimenting 
with pure cultures they found that the ferments which ‘* turn” 
wine do also produce mannite from levulose. Roos § had pre- 
viously argued that the occurrence of mannite in some wines 
depends primarily on the action of micro-organisms on sugars in 
the must, and not necessarily upon the existence of mannite in 
the fruit. ? 
Gerhardt, || in his time, remarked: ‘‘ Since the mannite found 
in plants is nothing more than a product of the metamorphosis 
of sugar, it may well be that at a certain epoch of vegetation no 
mannite would be found.” In this point of view the well-nigh 
constant occurrence of mannite in adult mushrooms and other 
* Cited in Chemisches Centralblatt, 1901, (2.) 648, 649. 
t+ Annales de l'Institut Pasteur, 1903, 17. 587; Abstract in Journal of the 
Chemical Society of London, 1903, 842. 745. 
t Comptes Rendus, 1898, 126. 1223 and 1904, 188. 228. Abstract in 
Journal of London Chemical Society. 1904, 861. 278. 
§ Journal de Pharmacie, 1893, (5.) 2'7. 405. 
| In his Traite de Chimie Organique, 2. 5738, note. 
