BACTERIA AND ICE 161 



perhaps, so surprising when we bear in mind the 

 remarkable feats of endurance exhibited by spores 

 which have with justification obtained for them a 

 prominent place amongst the so-called curiosities 

 of bacteriology. But of more interest than their 

 mere survival in these circumstances is the fact 

 that, on being restored to animation or, in other 

 words, released from their ice-prison these 

 bacteria were discovered to have retained all 

 their pathogenic properties, this period of en- 

 forced rigidity having in no way affected their 

 disease-producing powers. 



Such results naturally only served to whet the 

 "scientific appetite for more, and the liquefaction 

 of air and of hydrogen placing much lower 

 temperatures at the disposal of investigators, 

 those bacteriologists who were fortunate enough 

 to command a supply were not long in availing 

 themselves of the opportunity thus given them 

 of further testing the vitality of micro-organisms. 



Botanists had already shown that exposure to 

 liquid air, which means a temperature of about 

 - 190 C, and to liquid hydrogen, which means 

 a temperature of about -250 C., did not impair 

 the germination powers of various descriptions 

 of seeds, such as those of musk, wheat, barley, 

 peas, vegetable marrow, and mustard, and that 

 their actual immersion in liquid hydrogen for the 

 M 



