1910] CURRENT LITERATURE 17 
fact that fertilization is very easily demonstrated in normally fertilized species 
makes the writer confident that the failure to find it in B. coelestis is evidence that 
it does not occur. The figures show only topography, without any details of the 
chromatin situation. A careful counting of chromosomes at critical stages, 
and a few figures at the stages which show whether a form is apogamous or not, 
would have extended the paper but little, and would have made unnecessary 
any further work upon the subject; but as it is, a forthcoming paper will deal 
with these details, the present one being preliminary —CHARLES J. CHAMBERLAIN. 
Spermatogenesis in Mnium.—As a result of their studies of several species 
of mosses, the Drs. VAN LEEUWEN-REIJNVAAN reported that in the last division 
of the spermatogenous cells a second numerical reduction of chromosomes takes 
place. Ina species of Mniwm having eight chromosomes in the last division, two 
long and two short chromosomes pass to the daughter cells. Wutson,?" studying 
Mnium hornum, in a preliminary note announces that no such reduction is found, 
ee! that me pris i bs. ter 3 is constant throughout spermatogenesis. The 
is quite large and contains a small nucleolus. 
A continuous spirem is not present, and the chromatic material appears as a 
number of small masses from which the chromosomes are formed. In the final 
division the axis coincides with the long axis of the cell, there being no diagonal 
division. Six chromosomes can easily be distinguished in the last division, 
and it is clear that no such reduction as described by the Drs. VAN LEEUWEN- 
REIJNVAAN takes place in Mnium hornum. 
It is to be hoped that the final paper will also deal with fertilization, for many 
_ investigators find some difficulty in accepting the account given by the Drs. VAN 
LEEUWEN-REIJNVAAN.—W. J. G. Lanp 
Hydrogen bacteria.—The epoch-making researches of WrNoGRADSKI (1887) 
on the sulfur, nitrite, and nitrate bacteria established the important fact of the 
existence of non-chlorophyll organisms that are obliged to manufacture their 
organic food by energy obtained from the oxidation of various simple inorganic 
substances. In 1906 various investigators reported the existence of bacteria 
that can oxidize hydrogen as the source of energy for assimilating CO.. The 
forms were shown to be capable of using organic food as well, and are therefore 
oe autotrophic, in contrast to the obligate autotrophic forms studied 
by Winocrapski. LeBEDEFF?? now makes a preliminary report of the main 
results of an extensive study of the metabolism of these forms. The fixing of 
100 c.c. of CO, requires the oxidation of 500-1500 c.c. of H,. The oxygen for the 
process is best obtained from atmospheric oxygen, but in absence of it nitrates 
can be decomposed as its source. The oxidation of H, still continues in the 
presence of organic food, but no CO, is fixed in that gas cores CROCKER. 
21 Witson, M., Preli iets note on the Seierre dopeenals of Mnium hornum. 
Annals of 2 24:235. 
22 LeBEDEFF, A. J., Ueber die Assimilation des Kohlenstoffes bei Wasserstoff 
oxydierenden SER Ber. D eutsch. Bot. Gesell. 27:598-602. 1910. 
