TOCHlXAt : STUDIES ON THE rHVSiOLOGY OF Fusarium Uni. 39 



They germinated \-igoroiisl}- and produced aerial mycelium. 

 In these results it may be said that the low temperature, as -2i°C., does 

 not harm the \italitj' of this fungus at least within 24 hours. 



Experiment 4. 

 Resistance of the fungus to high temperature. 

 I have investigated the resistance with wet heat. The test tubes, which 

 contained 10 cc. of nutritive solution, wore inoculated with a bit of mycelium 

 and the chlamydospores of the fungus. The test tubes were incubated at the 

 high temperature in a self-regulating water bath, and with some interval they 

 were removed to an incubator at 25°C. I have adopted 50°C. and 6o°C. 

 for the high temperature, and i to 6 hours for the intervals. The results 

 obtained were as follows : 



Temperature Intcr\-a!s 



I hr. 2 hr. 3 lir. 4 hr. 5 lu". 6 hr. 



5o°C. + + + --- 



6o°C. + + ± - - - 



-f- shows living. — shows died. 



± shows some tubes living, some died. 

 Every sample was triplicated. 



The fungus maintained its vitality in this nutritive solution exposed for 

 three hours to the temperature So'^C. By heating at 6o°C. for three hours, the 

 fungus in one tube maintained its vitality, while that in the other two tubes 

 was killed. 



Above three hours at both temperatures none retained their vitality. 



V Summary 



I. On several kinds of the artificial cultural medium, this fungus develops 

 well producing conidia, and when the culture become old chlamydospores are 

 formed. 



