183 



able to withstand the heat and desiccation for two (2) weeks, though 

 the culture that had been in the heat for one week germinated readily. 



3. Resistance to Heat of Zygotes Upon Oven-dried Bread. — The 

 bread was first dried in an oven, the temperature of which was kept at 

 110-120 degrees centigrade for several hours. In each test tube was 

 placed a small cube of this bread, which had been inoculated with 

 zygotes; the test tubes were plugged with cotton, and then placed in 

 the oven at 100 degrees centigrade for different lengths of time ranging 

 in close series from 1 min. to 25 min. After the cultures were removed 

 and allowed to cool the bread was moistened with sterile water. In 

 every instance, up to and including those remaining in the heat for 

 17% minutes, zygotes were produced within a week; but in those cul- 

 tures remaining in the heat 20, 22 ¥2, and 25 minutes, no zygotes were 

 formed, though there was a vigorous growth. 



Other cultures were placed in the oven at a temperature of 60 

 degi'ees centigrade. This experiment is scarcely complete, since the 

 various lengths of time were not close enough together to warrant any 

 conclusions. Cultures remaining in this heat for one week grew vigor- 

 ously after being removed to suitable environment; but those remaining 

 in the heat for five weeks failed to germinate after being removed to 

 room temperature and moistened. 



The third set of experiments under this heading was placed in an 

 oven at seventy (70) degrees centigrade, the duration being from four 

 (4) days to three (3) weeks. New zygotes produced growth after they 

 had remained at seventy (70) degrees centigrade for two (2) weeks, 

 though at the end of three (3) weeks there was no sign of germina- 

 tion. Old zygotes did not resist the heat as long, the longest duration 

 being one week. 



4. Resistance to Heat of Zygotes in Presence of Small Amount of 

 Moisture. — In these cultures the amount of moisture was that which is 

 ordinarily found in fresh bread. Experiments placed in the oven at 

 sixty (60) degrees centigrade for one week showed no growth after 

 being removed to favorable environment and neither did cultures after 

 being in the oven for only forty-eight (48) hours at this temperature. 



5. Resistance to Heat of Zygotes in Presence of Large Amount of 

 Moisture. — These experiments were perfoimed, first, by thoroughly soak- 



