774 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
thus the power, like the Bacillus ethaceticus , of distinguishing between 
the isomers mannitol and dulcitol. 
(3) In the fermentation of dextrose and mannitol, the principal 
products are ethyl-alcohol and acetic acid, with a smaller proportion of 
formic acid, and traces of a fixed acid, in all probability succinic acid. 
(4) The gaseous products are carbonic anhydride and hydrogen. 
(5) The ethyl alcohol, volatile acids, carbonic anhydride, and 
hydrogen, approximate to the molecular proportions 9C. 2 H 6 0, 4C 2 H 4 0 2 , 
12C0 2 8H 2 . 
(6) The productions of which may be most readily referred to the 
following equations: — 6C 6 H 14 0 6 + OH 2 = 9C 2 H 6 0 + 4C 2 H 4 0 2 
+ 10CO 2 + 8H 9 , which is followed by 4C 2 H 4 0 2 + 2CaC0 3 = 2C0 9 
+ 20H 2 + 2Ca(6 2 H 3 0 2 ) 2 . 
Diastatic Ferment in Green Leaves.* — Prof. S. II. Vines criticizes 
the statement of Wortmann f that green leaves contain no diastase, or 
not a sufficient quantity to effect the transformation of starch into sugar 
which takes place in them. He gives details of experiments which 
appear to him to establish the fact that a diastatic ferment is present in 
green leaves ; and, though the quantity found at any moment may be 
comparatively small, it is probable that the total amount secreted during 
a night would suffice to effect the observed conversion of starch into 
sugar. 
y. General. 
Evolution of Parasitic Plants.^— Mr. T. Meehan believes that the 
distinction between parasitic and non-parasitic plants is by no means an 
absolute one ; but that many species usually parasitic will grow in the 
ordinary way in the soil, and have, as now existing, acquired parasitic 
habits. Many species of Santalaceae are partial parasites. Sarcodes 
sanguinea and Orobanche will germinate in ordinary garden soil, and 
go on with their development through all its stages ; and Monotropa 
will grow in soil with only the slightest modicum of vegetable matter. 
Exudation of Sap by Mangifera.§ — M. H. Leveille records a singu- 
lar effect of the wet season on Mangifera indica. It produced no fruit ; 
but from the extremity of the young shoots was exuded a yellow viscous 
saccharine fluid, identical with that ordinarily contained in the mango- 
fruit. He regards this as the elaborated sap which, not being required 
for the development of the fruit, is thus thrown off. 
B. CRYPTOGAMIA. 
Cryptogamia Vascularia. 
Life-history of Isoetes.|| — Prof. D. H. Campbell has carefully fol- 
lowed out the development of the female prothallium and embryo of 
Isoetes echinospora var. Braunii. His researches confirm the view of the 
affinity of Isoetes with the Filicineae rather than with the Lycopodineae. 
The development of the oophyte resembles much more nearly that of 
* Ann. of Bot., v. (1891) pp. 409-12. t Cf. this Journal, ante , p. 221. 
X Bull. Torrey Bot. Club, xviii. (1891) pp. 210-2. 
§ Bull. Soc. Bot. Fiance, xxxviii. (1891) p. 286. 
|| Ann. of Bot., v. (1891) pp. 231-58 (4 pis.). 
