ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
341 
Enzymes of Schizo-Saccharomyces octosporus and Saccharomyces 
Marxianus.* — It is extremely probable that the fermentation of a poly- 
saccharid is brought about by Saccharomycetes through the agency of 
enzymes, which convert it into a monosaccharid. Such enzymes can be 
obtained from yeasts dried in air by extraction with water. The solution 
of ordinary beer yeast contains not only invertin, which splits up cane- 
sugar, but also glucase, which decomposes maltose. So, too, kefir- 
grains and milk-sugar yeast produce lactase, which decomposes milk- 
sugar. From these considerations Herren E. Fischer and P. Lindner 
concluded that Scliizo-Saccharomyces octosporus , which ferments maltose 
but not cane-sugar, does not produce invertin, though it docs glucase. 
Experiment converted suspicion into certainty ; for the enzyme solution 
had no action on cane-sugar, though it decomposed maltose with facility, 
both in the presence and absence of chloroform. After one part of 
maltose, with 10 parts of the solution, had been heated for 20 hours 
at 33°, the decomposition was so far advanced that by the phenylhydrazin 
test it was found that the quantity of glucosazon was considerably* 
greater than that of the maltosazon. Attempts to isolate the enzymo 
were not successful. The enzyme solution also acted on a-methyl- 
glucosid, but more slowly than on maltose. 
Saccharomyces Marxianus behaved in just the opposite way : as it 
fermented cane-sugar but not maltose. An aqueous extract of this yeast 
was able to completely invert 10 per cent, cane-sugar at 33° in 20 hours. 
Under similar conditions no demonstrable hydrolysis occurred with 
maltose. Just as little as maltose was a-methylglucosid affected. 
Fungi which form a Transition Group between Moulds and Sac- 
charomyces Yeast. f — Among the fungi which produce sprouting cells 
with endogenous new formations there is a group, says Herr A. 
Jorgensen, of special interest, because these fungi form a transition group 
in the sense that, under certain circumstances, the mould stage is com- 
pletely in abeyance, and the fungus developes only a yeast vegetation,, 
yet under others the mould and yeast stages occur simultaneously during 
the whole of development. The determination of these variation phe- 
nomena appears to depend on the nature of the cultivation medium and 
the environment. This group is also important because it developes with 
especial power in hopped wort, and may impart to beer a disagreeable 
flavour and odour. Full details are promised in a forthcoming laboratory 
report. 
Variation of Yeast Cells4 — When Eeess described alcoholic fer- 
mentation fungi, the size and shape of the cells was taken as the basis of 
classification ; but, as Prof. E. C. Hansen urges, the distinguishing 
characters lie not in the size and shape per se, but in the form and size 
contingent upon particular conditions of cultivation. But not only in 
size and shape, but in other characters, may there be variation, such as 
spore-formation. Under certain conditions (cultivation in aerated wort 
at a temperature above the maximum for spore-formation) certain typical 
* Ber. Deutsch. Cliem. Gesellsch., xxviii. No. 8. See Bot. Centralbl., Ixiv. 
(1895) p. 335. 
f Centralbl. f. Bakteriol. u. Parasitenk., 2 te Abt., ii. (1896) pp. 41-4. 
X Ann. of Bot., ix. (1895) pp. 549-60. (Jf. this Journal, ante y p. 96. 
