.TOXIC EFFECTS ON FUNGI 127 



Saccharomyces a product he calls zymase, which produces 

 a characteristic and vigorous fermentation, independent of 

 living protoplasm. It is considered probable, although 

 not yet proved, that the yeast cells excrete zymase into the 

 surrounding liquid, and consequently fermentation takes 

 place outside and not inside living cells. In a later com- 

 munication Biichner announces that he has obtained 

 zymase from dead yeast. 



Biffen, Ann. Bot., 13, p. 363 (1899). 



Biichner, Ber. d. deutsch. Chem. Ges., 30, p. 117 (1897); 

 idem, 33, p. 3307 (1900). 



Ward, Ann. Bot., 2, p. 319 (1889). 



Wehner, Comp. Rend., 117, p. 332 (1893). 



Went, Koninkl. Akad. van Wetensch. te Amsterdam, 

 Feb. 23, 1901, p. 489. 



Bourquelot, Bull. Soc. Myc. France, 9, p. 189 (1893). 

 This author mentions the occurrence of a ferment in 

 Aspergillus niger capable of transforming trehalose into 

 glucose. 



Green, The Soluble Ferments and Fermentation, London, 

 1899. Contains full account of the enzymes occurring in 

 Fungi. 



Vines, 'The Proteases of Plants,' Ann. Bot., 18, p. 289 

 (1904). 



TOXIC EFFECTS OF DIFFERENT SUBSTANCES 

 ON FUNGI 



According to Clark, fungi in general are much more 

 resistant to deleterious agents than are the higher plants. 



