ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
243 
to any alga. His Lithopytliium gangliiforme also bears a strong resem- 
blance to the hyptue of Verrucaria calciseda * ; but M. Bornet has not 
been able absolutely to determine their identity. 
Hansen on Pasteur’s Pure Yeast.j — Herr E. C. Hansen, in an 
article entitled “What is Pasteur’s pure yeast?” replies to the attacks 
of Duclaux and Yelten, both of whom seem to prefer Pasteur’s method 
for obtaining a pure yeast cultivation to that of the author. 
Duclaux eventually limited his strictures, admitting that, as far as 
bottom yeast was concerned, the author had effected a reform in brewing, 
but maintained his position with regard to top yeast. 
Yelten’s contention was that Hansen had made a bad mistake in 
introducing into brewery practice a yeast consisting of a single species 
or race, his (Velten’s) view being that brewers’ yeast was composed of 
several kinds. The author then proceeds to show that the method 
advocated by his critics not only fails to obtain a pure cultivation, but 
if any disease-yeast be present matters become worse, and that therefore 
this method is useless for practical brewing purposes. 
The author then proceeds to show that Pasteur’s method had in view 
the purification of yeast from bacteria, and did not take into consideration 
the action of yeast-fungi, the addition of tartaric acid to the saccharine 
medium being only intended for the suppression of the bacteria. 
The author points out that the commonest and most dangerous 
diseases to which low-fermented beer is liable are caused by certain kinds 
of Saccltaromyces, a fact which precluded the possibility of purifying 
the yeast by Pasteur’s method. 
The author’s own researches further proved that under the term 
Saccharomyces cerevisiae were included all sorts of top and bottom yeasts, 
from which the most suitable variety ought to be chosen. When put 
into practice, the value of these principles was soon recognized by the 
brewing trade. 
Hew Genera of TJredinese.J — Prof. G. von Lagerheim describes four 
new genera of Uredinese from Ecuador, viz. : — 
Pucciniosira. M early allied to Endophyllum, the teleutospores being 
abstricted in chains and surrounded by a pseudo-peridium ; but they are 
two-celled, and intermediate cells are formed between them which remain 
attached as appendages to the base of the spores. P. Solani on a species 
of Solarium. 
Chrysopsora. A connecting link between Puccinia and Coleosporium. 
Only pycnids and teleutospores are known. Each teleutospore-cell 
divides by three thin septa into four cells, from each of which is deve- 
loped a unicellular promycele or sterigma, which abstricts from its apex 
a single large ovate sporid. C. Gynoxidis, on more than one species of 
Gynoxis. 
Alveolaria. Occupies an isolated position from the structure and 
arrangement of its teleutospores, which only are known. The groups 
of spores form round, often concentric, or elongated groups, forming 
columns on the under side of the leaf or on the leaf-stalk ; the spores are 
* Cf. this Journal, 1891, p. 383. 
t CR. Travaux du Laborat. de Carlsberg, iii. (1891 ) pt. 1. 
J Ber. Deutseh. Bot Gesell., ix. (1891) pp. 314-8. 
