376 MICRO-ORGANISMS AND FERMENTATION. 



from the same ascus may fuse together, and further that the 

 spores which grow together by fusion may then develop to 

 asci with spores without previously forming new cells (compare 

 Hansen's experiments with wine yeast, Johannisberg II.}. He 

 finally showed that by the fusion and germination of spores a 

 combination of their cell nuclei and a subsequent division takes 

 place as soon as the promycelium has reached a certain size. 

 Guilliermond described this process as conjunction with isogamy. 



Whilst in the case of Schizosaccharomycetes and -Zygo- 

 saccharomycetes a conjunction takes place between the vege- 

 tative yeasts converting these into an ascus, in this case con- 

 junction takes place between the spores and even before they 

 germinate. 



Will discovered that the spores may sometimes be more or 

 less distinctly stained to a bluish-green with iodine in potassium 

 iodide (a similar colour to that given by Bact. Pasteur. Hanseri). 

 In old cultures (Fig. 82) there is a strong tendency to 

 form mycelia, but it is only exceptionally that portions are 

 found where the links are closely bound together, and only 

 display slight contractions. Such portions are provided with 

 distinct and straight septa. Every cell of such a colony can 

 form spores as w T ell as buds. Amongst them odd shapes and 

 very large, strongly branched cells are found. It is character- 

 istic of this species that the cells die off within two years in 

 aqueous sugar solutions, Avhilst most of the known Saccharo- 

 mycetes live much longer in this liquid. The tempera- 

 ture limits for budding in wort are 37 to 38 C. and 3 to 

 1 C. The maximum temperature for spore-formation is 32 

 to 32-5 C., the minimum 3 to 6 C., the optimum 30 to 31 C. 

 (18 to 20 hours). (Nielsen.) 



Holm has repeatedly found 8. Ludwigii in fermenting apple 

 and gooseberry juice, as well as in English and American cider. 

 Behrens found a Saccharomycetes on hops in which the germinal 

 tubes of the spores fuse together as is the case with S. Ludwigii. 

 The cells are large, round, and oval, the spores round and 

 refractive. At 18 to 20 C. spores appear in 22 hours. No 

 film-formation takes place. It ferments dextrose, laevulose, 

 and maltose, but does not invert saccharose nor ferment 

 lactose and galactose. 



