1911.] Substances upon the Auto fermentation of Yeast. 459 



The behaviour of alcohol, therefore, is in accord with that of urea, although 

 the effect is not quite so simple. 



Summary. 



1. All dissolved substances which plasmolyse the yeast-cell also cause a 

 large increase in the rate of autofermentation. 



2. Substances such as urea, which even in concentrated solution do not 

 produce plasmolysis, have no accelerating effect. 



3. Toluene produces a similar effect to concentrated salt solutions. 



4. The effect produced by salts is probably a direct result of the con- 

 centration of the cell contents due to plasmolysis, but in the case of toluene 

 it is possible that some other factor (such as disorganisation of the cell, or 

 hormone action) is concerned. 



EEFEEENCES. 



1. Harden, Thompson, and Young, ' Biochem. Journ.,' 1910, vol. 5, p. 230. 



2. Paine, ' Koy. Soc. Proa' (in press). 



3. Neubauer and Fromherz, 'Zeitschr. f. Physiol. Cliem.,' 1911, vol. 70, p. 326. 



4. Neuberg and Hildesheimer, 'Biochem. Zeitschr.,' 1911, vol. 31, p. 170. 



5. Neuberg and Tir, ibid., 1911, vol. 32, p. 323. 



6. Neuberg and Karczag, ibid., 1911, vol. 36, p. 60. 



7. Overton, < Jahrb. f. Wiss. Bot.,' 1900, vol. 34, p. 670. 



8. Lepeschkin, 'Ber. Deutsch. Bot. Ges.,' 1911, vol. 28, p. 383, and vol. 29, p. 349. 



9. Meyer, Hans, 'Beport Int. Cong. Applied Chemistry,' 1909, IVa, vol. 2, p. 37. 

 10. Armstrong, H. E. and E. F., ' Roy. Soc. Proc.,' B, 1910, vol. 82, p. 588. 



