426 . The American Naturalist. [May, 
BOTANY. 
What is Mycoderma ?—1. In my papers on the yeasts, I have 
mentioned the doubtful position of the sprouting fungus Myco- 
derma which morphologically and systematically stands near to the 
Saccharomycetaceae. From the latter, it is easily distinguished on 
account of its high refractive power, the cells being also rectangular, 
not spore-bearing, and very apt to aggregate in masses, or in a film. 
When beer, wine, or other sugar-containing liquids are exposed to 
air, the Mycoderma will very soon form a gray, greasy looking, uneven 
film on the surface of the liquid. Hitherto, it was supposed that this 
fungus could not form alcohol; Lasché has, however, found four spe- 
cies which yield 4 to 2} vol % of alcohol (See Der Braumeister, Chi- 
cago, 1891, No. 7); Winogradsky found that the morphology of the 
cells changes according to the amount of organic material given 1m å 
constant solution of inorganic nutritive matter. (See Centralbl. f. Bak- 
teriol. u. Paras., 1884, p. 164). Lately, F. Lafar showed that at least 
one species will produce acetic acid. (Ibid, XIII, p. 684-697 1893, 
w. pl.). 
In 1879 Hansen expressed his opinion that there were undoubtedly 
more than the two species—W. cerevisiae and M. vini—deseribed by 
Pasteur (Studies on fermentation, pp. 77,110, pl. IV) im existence. 
‘hese two named species cannot be distinguished from each other, 
they must be regarded as synonyms to all the species—at po 
known. The macroscopic appearance of these fungi was mentio 
in the January No. of the American Monthly Microscopical Ji "y 
2. The name Mycoderma was given by Pasteur to the bai 
acetic fermentation. As far back as 1834, Kützing determined 
vegetable nature of this ferment; he named it Ulvina aceti. asteur 
(See Etudes sur la vinaigre) and Turpin took the question up aga! 
and studied the morphology of the organism. In 1879, Hansen be 
a new species which assumes a blue color with iodine or IKa» while f 
other species became yellow when thus treated. He found, lately,“ 
another species which is also colored blue with iodine, namely, per 
cies kiitzingianum. The genus-name was, on the suggestion of Te? 
changed into Bacterium. (See Berichte der Deutschen 
Gesellschaft, 1893, p. (69-73). Three species of acetic 
‘Edited by Prof. C. E. Bessey, University of Nebraska, Lincoln, Nebraska, 
fermentatio 
