Doenu'Hs {Allg. Biau. ii. llopj. Ztg., V, 2225, 1897) ex- 

 posed beer yeast to the lemi)eratiire of liquid air for 6 

 mimiles; tlie yeast retained its vitality. 



Kiii-clicr (lOni) found that Sacrliaronn/res cerevisiae. 

 cultured on agar slants, survived a 1 to 8 day action of a 

 temperature of -70°, as well as a 13 hour exposure to 

 -183° to -192° in liquid air. 



Macfadyen and Rowland (1902) kept yeasts which had 

 been washed, pressed and wrapped in paper, immersed in 

 liquid air for 6 months; neither the vitality nor the 

 physiological properties of the organisms were impaired. 



According to Kadisch (1931), pathogenic yeasts sus- 

 pended in 0.85'/ sodium chloride were not killed after 24 

 lionrs at -180°, nor after 3 hours at -252°, nor after 2 

 hours at -268.8°, though the latter treatment caused a 

 consideral)le delay in development. In a further test he 

 cooled the yeasts by degrees from room temperature to 

 -268.8°, where they stayed for 2 hours; thereupon he 

 brought them down to the temperature of -272°, which 

 was maintained for 14 hours. He then raised the tem- 

 perature to - 268.8° and kept it at this point for another 

 2 hours ; finally, lie l)rought the organisms by degrees back 

 to room temperature. There was no loss of vitality, but 

 merely a slowed development, and the author concludes 

 that cold alone cannot produce the death of the micro- 

 organisms. 



B. Tanner and Williamson (1928) exposed ampullae 

 containing 2 cc. of a suspension of yeast in physiological 

 saline, to - 15° for varying lengths of time up to about 3 

 years; most of the yeasts were markedly injured after 

 that time. 



Schumacher (1874) observed that in fresh yeast, ex- 

 posed for 15 minutes to -113°, many of the cells were 

 killed. The younger ones with smaller vacuoles and those 

 still devoid of vacuoles remained alive and were capable 

 of budding. 



Pictet and Yung (1884) exposed Saccharomyces cere- 



