SACCHAROMYCES MEMBRANE FACIENS 249 



Spore Formation. Spores are not freely developed ; on solid 

 media they are more frequent, being usually oval or kidney-shaped. 



Film Formation. The film develops very slowly, and consists of 

 oval and short sausage-shaped cells. 



Biological Characters. In beer-wort it is not very active. It 

 does not ferment maltose, but acts strongly on saccharose, which it 

 inverts and then ferments with great rapidity. It also acts upon 

 dextrose. 



SACCHAROMYCES MEMBRAN.EFACIENS. 



Forms a bright yellow, tough scum on beer- wort, composed of long 

 and sausage-like cells, occurring either singly or closely packed 

 together. 



Spore Formation. Spores are formed rapidly. 



Biological Characters. Nutrient gelatine is liquefied. It does 

 not cause any fermentation of ordinary carbohydrates and does not 

 invert cane sugar. 



SACCHAROMYCES EXIGUUS. 



Found in German yeast by Hansen. It forms no mycelial threads 

 on beer- wort or on solid media. It forms spores but sparsely. The 

 film is very delicate, and consists of short rod-shaped or ovoid cells. 

 It causes the same changes in sugars as the Saccharomyces marxianus. 



SACCHAROMYCES ACIDI LACTICI. 



Occurs as ellipsoidal cells. 



On Gelatine Plates and Agar Surface Cultures it forms white, glistening 

 colonies. 



In Gelatine Slab Cultures, club-shaped outgrowths are given off from 

 the inoculation track. 



On Potatoes it forms a brownish coating. 



Milk is coagulated, an acid being formed. In solutions of milk sugar 

 it forms alcohol. 



MYCODERMA CEREVISLE ET VINI. 



Like all other forms of mycoderma it is distinguished from the 

 saccharomyces by forming no spores (ascospores). 



