26 



SOME FUNGOUS DISEASES OF ECONOMIC IMPORTANCE. 



Experiment No. 11. 



1,200 c. c. formalin per 1,000 cubic feet of air space. 

 Temperature before mixing reagents, 78° F. 



Thielaviopsis cultures in petri dishes. 



Initial 

 growth 

 of fungus. 



Vigorous 

 growth 

 of fungus. 



Checks; fungus not exposed to formaldehyde gas 



Fungus exposed 15 minutes 



Fungus exposed 30 minutes 



Fungus exposed 60 minutes 



Hours. 



29 















Hours. 



Experiment No. 18. 



1,200 c. c. formalin per 1,000 cubic feet of air space. 

 Temperature before mixing reagents, 78° F. 



Thielaviopsis cultures in petri dishes. 



Initial 



growth 



of fungus. 



Vigorous 

 growth 

 of fungus. 



Checks; fungus not exposed to formaldehyde gas 



Fungus exposed 15 minutes 



Hours. 



23 















Hours. 

 50 

 



Fungus exposed 30 minutes 







Fungus exposed 60 minutes 











Several duplicate experiments were made with this quantity of gas 

 and the growth was negative in every case. 



Experiment No. 19. 



1,250 c. c. formalin per 1,000 cubic feet or air space. 

 Temperature before mixing reagents, 76° F. 



Thielaviopsis cultures in petri dishes. 



Initial 



Vigorous 



growth 



growth 



of fungus. 



of fungus. 



Hours. 



Hours. 



23 



50 



























Checks; fungus not exposed to formaldehyde gas. 



Fungus exposed 15 minutes 



Fungus exposed 30 minutes 



Fungus exposed 60 minutes 



Experiment No. 20. 



1,250 c. c. formalin per 1,000 cubic feet or air space. 

 Temperature before mixing reagents, 80° F. 



Thielaviopsis cultures in petri dishes. 



Initial 

 growth 

 of fungus. 



Vigorous 

 growth 

 of fungus. 



Checks; fungus not exposed to formaldehyde gas 



Hours. 

 24 

 

 

 



Hours. 

 50 



Fungus exposed 15 minutes. . . 







Fungus exposed 30 minutes 







Fungus exposed 60 minutes 











171 



