276 TEXT-BOOK OF FUNGI 



alcohol and carbonic acid. The lactic acid bacteria 

 precipitate the casein as a flocculent substance, easy of 

 digestion, and also impart a pleasant acid flavour to the 

 liquor. 



Tibi, a substance found on the stems of species of 

 Cactus in Mexico, and used for producing a fermented 

 beverage, has been shown by Lutz to consist of a bacterium 

 and a yeast in symbiotic union. Ward has also shown that 

 the production of ginger-beer is due to the work of bacteria 

 and yeast-cells respectively, and suggests a symbiotic 

 condition between the two organisms. 



Barker, Phil. Trans. Roy. Soc., 194, p. 467 (1901). 



Journ. Federated Inst. of Brewing, 8, p. 26 

 (1902). 



Beyerinck, Centralbl. fur Bakter-u. Parasitenkunde, 16, 

 p. 49. 



Biichner, Ber. d. deutsch. chem. Gesell., 30, p. 117 

 (1897). 



Green, Ann. Bot., 12, p. 491 (1898). 



Hansen, Meddels. fra Carls. Lab., 2, p. 152. 



,, C. R. Trav. Lab. Carlsberg, 5, p. i (1900). 



Jorgensen, Micro-organisms of Fermentation, London 

 (1899). 



Lutz, Bull. Soc. Myc. France, 15, p. 157 (1899). 



Ward, Trans. Phil. Roy. Soc., 183, p. 125 (1893). 



Wager, Ann. Bot., 12, p. 449 (1898). 



ASCOMYCETES 



The enormous assemblage of species included in the 

 present Order agree in having a definite number of spores 

 usually eight produced by free-cell formation in a 



