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Resistance of Mucor Zygotes. 



Mildred Nothnagel — Florida Experiment Station. 



In the fall of 1916, while attending Indiana University, various 

 experiments were begun to test out the resistance of Mucor zygotes 

 and spores to desiccation, to heat, and to different chemicals. 



Fortunately the writer had a good culture of zygote material from 

 which fresh zygotes could always be raised. Since the zygotes are sup- 

 posed to be more resistant than the asexual spores, the experiments were 

 made with the former in order to make them more conclusive. 



After sterilizing the bread, inoculating it with zygotes, placing 

 in a dark place, room temperatures, zygotes in unlimited number would 

 be found in 5 to 7 days. 



The work was carried out along several lines, and in all cases, un- 

 less otherwise stated, zygotes that had been just freshly matured, and 

 those a year old, were used in order to make comparison. 



Outline of Work. 



1. Resistance of zygotes to desiccation. 



2. Resistance to heat of zygotes in the desiccator. 



3. Resistance to heat of zygotes upon oven-dried bread. 



4. Resistance to heat of zygotes placed upon bread with its normal 

 amount of moisture present. 



5. Resistance to heat of zygotes in presence of large amount of 

 moisture. 



6. Resistance of zygotes to various chemicals. 



In all the experiments the utmost care was used to have everything 

 sterile and, in case water or nutrient material had to be added, every 

 precaution was taken so that spores from the outside would not be 

 introduced. Control experiments were run for the purpose of checking. 



1. Resistance of Zygotes to Desiccation. — Into sulphuric acid desic- 

 cators were placed numerous cultures of the one-year zygotes as well as 

 the freshly matured zygotes with no nutrient material. These cultures 



