SACCH. PASTORIANUS III. 



Film-formation : 

 At 34 C. no film-formation occurs. 



26-28 feebly-developed film-specks 



are seen after . 7-10 days. 



20-22 8-15 * 



13-15 10-25 \ 



6- 7 1- 2 months. WFig. 71. > 



3- 5 5- 6 j 



2- 3 no film-formation occurs. 



Microscopic appearance of the cells in the films : 



At 20 to 28 C., almost the same forms as in the sedi- 

 mentary yeast ; also irregular sausage-shaped cells. 



At 15 to 3 C., mostly oval and round cells. 



In old cultures of films the cells are smaller than in the 

 sediment ; very irregular and sometimes almost thread-like 

 cells are found. 



Streak cultures of this species in yeast-water gelatine give 

 growths with comparatively smooth edges after sixteen days 

 at 15 C., and in this respect it also differs from the following 

 species. 



Saccharomyces validus or Saccharomyces Pastorianus III. 

 Hansen. (Figs. 72, 73.) 



Top-fermentation yeast. 



Sedimentary forms grown in wort : Mostly elongated, 

 sausage-shaped, but also large and small, oval, and round cells 

 (Fig. 72). When this species is cultivated in wort near the 

 temperature maximum for growth, the vegetation consists of 

 round and oval cells. The temperature limits for budding 

 in wort are 39 to 40 C. and 0-5 C. 



It was separated from a bottom-fermentation beer which 

 showed yeast-turbidity, and has been proved by Hansen to- 

 be one of the species which produce this disease. Recent 

 experiments of Hansen show that this disease-yeast possesses 

 another peculiar property its addition will in certain cases 

 effect a clarification when the fermenting wort has an opal- 

 escent appearance. 



According to investigations made by the author, a strong 

 infection of low-fermentation yeast with this species may in 



