228 FAMILY OF SACCHAROMYCETACEAE 



nusii. Hansen l later isolated Endomyces magnusii. Rose has found 

 this yeast since then under the same condition. 



Saccharomyces Ludwigii possesses variable shape and dimensions; 

 some cells are elliptical, others are elongated, tubular or with the shape 

 of a lemon. (Fig. 96.) The cells multiply by a process intermediate 

 between budding and transverse partition. They form generally at 

 both extremities, rarely laterally, a projection, a sort of a bud which, 

 when it has attained a certain size, separates itself from the mother 

 cell by a thin wall accompanied by a slight tightening of the neck. 

 The temperature limits for budding in beer wort are: minimum, 

 1-3 C.; maximum, 37-38 C. 



In old cultures especially on gelatin, Saccharomyces Ludwigii shows 

 a manifest tendency to produce well developed rudimentary myceliums 

 which resemble a true mycelium. These forma- 

 tions are made up of a series of budding ramify- 

 ing filaments. The cross walls are very marked 

 but almost always accompanied by a slight con- 

 striction and the units easily separate. Each of 

 the cells in the mycelium is able to bud and 

 form ascospores. Long branching units with walls 

 ' _ Saccharo- ma y be seen in the mycelium. (Fig. 5.) By the 

 mycodes Ludwigii . presence of these mycelial formations, Sacch. Lud- 

 wigii seems to offer an intermediate step between 

 the Endomyces and the yeasts. 



Ascospores form easily in water solutions of sugar, on wort gela- 

 tin in yeast water, on slices of carrot and even in liquid wort. They 

 develop equally in numbers on plaster blocks. 



According to Nielsen 2 the maximum temperature for sporulation 

 on plaster blocks is 32 to 32.5; the minimum is between 3 and 6 

 and the optimum between 30 and 31 C. 



The ascs may contain from two to four ascospores, rarely more, 

 but almost always there are four. These are round and about 3 or 

 4 IJL in diameter. Germination is accomplished in a special manner 

 which has been described at the beginning of the book and which will 

 not be repeated here. It is generally preceded by a sexual process 

 which Guilliermond 3 has described and which is comparable to par- 

 thenogamy. (Figs. 25 and 26.) After the ascospores have swelled they 



1 Hansen, E. C. Ueber die im Schleimfliisse lebender Baume beobachteten 

 Mikroorganismen. Cent. Bakt. 5, 1889. 



2 Nielsen, J. C. Sur le dev. des spores des S. membranaefaciens, anomolous 

 et Ludwigii. Comp. Rend, des trav. du lab. de Carlsberg, 3, 1891. 



3 Guilliermond, A. Recherches sur la germination des spores et sur la con- 

 jugaison dans les levures. Rev. gen. de Bot. 17, 1905. 



