144 A. W. BENNETT, 
becomes absorbed or coalesces with the former. The 
daughter-cells then appear united as if they originated from 
cell-division rather than free cell-formation (fig. 1, g, ). 
The process of free cell-formation now described agrees in 
every particular which is capable of observation with the 
process by which the ascopores are formed in the asci of 
the Ascomycetes, as described by de Bary, Hofmeister, and 
Woronin. Reess, therefore, without hesitation, terms the 
mother-cells asci, the daughter-cells ascospores, and the 
Saccharomyces an Ascomycete in the broadest sense of the 
term. 
The germination of the ascospores has been traced as fol- 
lows:—When asci containing mature spores are placed in 
beer-wort, the spores begin at once to swell up strongly, but 
often unequally ; their membranes coalesce with the wall of 
the ascus, if this has not already taken place. After fourteen 
or sixteen hours the true germination of the assemblage of 
spores commences, all those in an ascus, or only some of them, 
putting out knob-like protuberances. These protuberances 
become filled from the contents of the spore, and grow into a 
cell usually ovoid in shape, like the ordinary “ buddings” 
from the Saccharomyces-cell. Larger cells are again formed 
from these by budding, followed by simple or branched fila- 
ments (fig. 2). The cells of these filaments are at first smaller 
than the ordinary ones of Saccharomyces cerevisie ; but when 
their number increases they become larger, and after a short 
time are indistinguishable from those produced in the 
ordinary way. 
We have, therefore, under certain circumstances, in beer- 
yeast an alternation of generations ; some of its vegetative cells 
developing into spore-forming asci or organs of reproduction ; 
the germination of the ascospores producing again a genera- 
tion reproduced by budding, similar to that from which it 
sprang. 
1 «Bulletin de l’Académie Impériale des Sciences de St. Petersbourg ’ 
vol. xvi, 1872, p. 513. 
