ALCOHOLIC FERMENTS. 161 



Spores strongly refractive to light. Wall of spores very 

 distinct. Size of spores 2 - 5 6 /*. 



Film-formation : 



At 38 C. no film-formation occurs. 

 33 34 feebly-developed film-specks are 



seen after 9 18 days. 



,,2628 711 



,,20-22 7-10 



" 13 ~ 15 " \ (Fir ^ I " 15 - 3 



6- 7 J ( ^ { 2- 3 months. 



5 no film-formation occurs. 



.Microscopic appearance of the cells in the films : 

 At 20 34 C. : Colonies frequent ; sausage-shaped and 

 curiously formed cells occur. 



FIG. 35. 



Saccharomyces cerevisiae I. Hansen. Film-forms at 15 6 C., 

 after Hansen. 



At 156 C. (Fig. 35) : The greater number of the cells 

 resemble the original cells ; isolated cells of different form. 



In old cultures of films all forms occur, including greatly 

 elongated mycelium-like cells (Fig. 36, p. 162). 



SACCHAROMYCES PASTORIANUS I. HANSEN. 

 (Figs. 37, 38.) 



Bottom-fermentation yeast. 



Sedimentary forms grown in wort: Mainly elongated, 



Ball.) at the ordinary room-temperature, the young vigorous cells obtained 

 are introduced into fresh wort, in which they are allowed to develop 

 for about twenty-four hours at 25 to 27 C. This growth is used for 

 the gypsum-block culture. 



