182 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
first place, to the action of bacteria ; whether within or without the dead 
cell, oxygen is indispensable to the process. It is accompanied by a 
number of different bacteria, and not by a single species as previously 
supposed, and mould-fungi are also present. In some cases (seedlings), 
indican is formed only in the light ; in other cases, both in the light and 
in the dark, but always more abundantly in the light. The following 
species, in addition to Indigofera , are named as indigo-plants : — Ecliites 
religiosa , Wrightia antidysenterica , Crotalaria Cunninghamii, C. turgida, 
C. incana. 
Influence of Oxygen on Fermentation.* — Dr. G. Korff, in his re- 
rearches on the influence of oxygen on fermentation, fermentation-energy, 
and reproductive power, in different yeast races under different conditions 
of nutrition, worked with pure cultures of Saaz, Frohberg, and Logos 
yeasts, and used solutions of cane-sugar or yeast-water and asparagin 
solution as nutritive media. The following general conclusions were 
arrived at. 
(1) Moderate aeration may favour the reproductive energy and re- 
productive power (Saaz and Frohberg), or lessen it (Logos). 
(2) Moderate aeration may raise the fermentation energy (Saaz and 
Logos), or lessen it (Frohberg). 
(3) Moderate aeration either favours the fermenting power (Frohberg 
and Logos), or is without influence (Saaz). 
(4) Oxygen always increases the reproductive energy ; and 
(5) Also the reproductive power, though moderate aeration may be 
even more favourable (Frohberg). 
(6) Oxygen diminishes the fermentation energy and power in all 
cases. 
(7) Hydrogen or total deprivation of oxygen inhibits the reproduc- 
tive energy (Saaz and Logos), or is without influence (Frohberg). 
(8) Hydrogen always causes a reduction of reproductive power ; and 
(9) Either induces a reduction of fermentation energy (Saaz and 
Frohberg), or is without influence. 
(10) Hydrogen augments the fermenting power (Frohberg and 
Logos), or exerts no influence (Saaz). 
Hence, under the given conditions, it would seem that reproductive 
power and energy, and fermentative power and energy, are, as far as 
these three yeasts are concerned, inversely proportional. The three 
illustrations show the ingenious apparatus used by the author in his ex- 
periments. For these and the numerous details of the experiments the 
original should be consulted. 
y, General. 
Origin of Gymnosperms and the Seed Habit.f — In his retiring 
Address as President of the Botanical Society of America, Prof. J. M. 
Coulter thus sums up his general conclusions on this subject. 
A great Gordaites plexus, more extensive than the one usually included 
under that name, represented the characteristic Palaeozoic seed-plants. 
It was probably derived from homosporous eusporangiate Filicales, 
* Centralbl. f. Bakt. u. Par., 2 te Abt., iv. (1898) pp. 465-72, 501-7, 529-35, 561-9, 
616-27 (3 figs.). t Bot. Gazette, xxvi. (1898) pp. 153-68. 
