262 FAMILY OF SACCHAROMYCETACEAE 



The temperature limits for budding on beer wort are a minimum 

 below 5 and a maximum of 40^11. The shape of the cell is the same 

 at the temperature limits as at the optimum temperature. A feeble 

 ring but no scum is formed at the end of 11 days. 



Sporulation is easily accomplished on slices of carrot and Gorod- 

 kowa's gelatin and the plaster block. The ascs contain from 1-4 



spherical spores, 2-2.5 jit in diameter. 

 Spores germinate exactly as those of S. 

 Chevalieri. On wort agar at 25 the yeast 

 develops after three or four days with a 

 train of white, moist colonies. The center 

 is slightly indented and the border slightly 

 sinuous. The center is thick and granular, 

 Fig. 121-G. Saccharomyces the periphery surrounded by a number of 



canals running out from the center. 



On wort agar stab cultures at the end 



Germination of Ascospores. 



shaped. On wort gelatin at 20 the colony is round with a slightly 

 raised center. There is no liquefaction of gelatin. The yeast has the 

 characteristics of a top yeast and causes a rather active fermentation 

 of beer wort. It ferments saccharose, dextrose, levulose, d-mannose, 

 lactose, d-galactose, and dextrine. 



SACCHAROMYCES CHEVALIERI. Guilliermond l 



This yeast was isolated in a wine fermentation from the Ivory 

 Coast. On beer wort at 25, this yeast forms an abundant white 

 sediment. When examined at the end of 24 hours, this sediment shows 

 large cells, spherical or oval in shape. Many give birth to long 

 buds sometimes in the form of sausages. A certain number of the 

 cells are elongated, but the round or oval cells are the most frequent. 

 The cells of this yeast belong to the ellipsoideus type. 



The dimensions of the cells vary between 5 and 9 fJL in length and 

 4 and 7 JJL in width. The average dimensions are about 5.53 /z long and 

 4.14 IJL wide. The cells are frequently united in small colonies of about 

 3-10 budding units. In older cells these colonies are generally spheri- 

 cal or oval, while the young cells have a tendency to elongate. 



The temperature limits for budding on beer wort are a minimum 

 below 5 C. and a maximum of 40-41 C. Near these temperature 

 limits the yeast has the same cellular forms as at other temperatures. 



1 Guilliermond, A. Monographic des levures rapportees d'Afrique occidentale 

 par la Mission Chevalier. Annales des Sciences Naturelles Botaniques, 19, 

 1914. 



