THE MYCOGONE DISEASE OF MUSHROOMS AND ITS CONTROL. 13 

 Table I. — Results of experiments with formaldehyde gas on cultures of the fungus. 



Experiment. 



Date. N o. 



Jan. 31 



Feb. 8 



He 



Mar. 



1 



3 



Mar. 



10 



24 



Mar. 



16 



5 



Apr. 



4 



1 6 



Apr. 



14 



*8 



Apr. 



20 



6 9 



Apr. 25 | 7 10 



Temper- 



Forma- 



Age (in 



ature 



lin (c. c.) 



days) of 



(°F.) 



per 1,000 



culture 



before 



cubic 



at time 



mixmg 



feet of 



of fumi- 



reagents. 



space. 



gation. 



55 



700 



21 



55 



700 



17 



55 



700 



7 



67 



700 



11 



65 



800 



16 



76 



900 



23 



58 



1,000 



12 



74 



900 



17 



76 



800 



9 



78 



700 



11 



73 



600 



13 



76 



500 



20 



Number of cul- 

 tures exposed 

 to formalde- 

 hyde gas for — 



!0 min- 

 utes. 



60 min- 

 utes. 



19 

 16 

 14 

 None. 

 11 

 10 



12 

 None. 



Num- 

 ber of 

 check 

 cultures 

 made. 



Growth (period in days) 1 of the fungus 

 in checks and in transfers made from 

 cultures exposed to the gas for 30 and 

 60 minutes, respectively. 



Check. 30 minutes. 60 minutes. 



3f. 



34 



54in3i. 



5in3J... 



5 in 34. 

 1 in 44. 



3 in 6 



Iin8 



2 in 18 



5 in 6 



3 in 7 



6in6 



1 in 7 



1 inl4 



Iinl7 



lin26 



Iin8i 



Iin20 



Iin25 



Iin28 



No growth. 



do 



....do 



No growth. 

 ....do 



1 in 84. 



1 in 26. 



Iin8. 

 Iin21. 



2 in 6. 

 2 in 8. 



Iin7. 



Iin21. 



Iin26. 



3in4J. 

 2 in 5J. 

 lin9J. 

 1 in 28. 

 1 in 5£. 

 No growth. 



Do. 

 1 in 38. 

 No growth. 



Do. 

 1 in 84. 

 1 in 17. 

 1 in 20. 

 1 in 10. 

 Iin23. 



Recapitulation of Results. 



Experi- 

 ment 



Tempera- 

 ture (°F.) 

 before 

 mixing. 



Formalin 



(e. c.) per 



1,000 cubic 



feet of 



space. 



Age (in 

 days) of 

 culture 

 at time 

 of fumi- 

 gation. 



Percentage of check cultures and transfers from cultures which 

 grew after exposure to formaldehyde gas for stated lengths 

 of time. 



No. 



Checks. 



• 15 t 



m mutes. 



30 

 minutes. 



60 

 minutes. 



90 

 minutes. 



184 

 hours. 



10 



76 

 73 

 78 

 55 

 55 

 55 

 67 

 65 

 76 

 76 

 74 

 58 



500 

 600 

 700 

 700 

 700 

 700 

 700 

 800 

 800 

 900 

 900 

 1,000 



20 

 13 

 11 

 21 



17 

 7 

 11 

 16 

 9 

 23 

 17 

 12 



83. 33 

 83.33 

 80 



100 



100 



100 



100 



100 



100 



100 



100 



100 



42.85 





13.33 



30 

 









9 



16.67 

 





 







8 









la 



58. 33 15. 38 





lb 





72.72 

 90.90 

 18.18 















36.36 



25 



34.35 



5.55 











8.33 







lc 









2 









3 









7 

 4 









 





6 







5 























1 The period for growth was reckoned to the time when an indication of grov/th of the fungus in the 

 transfers first appeared. 



2 In experiment 4, 17 cultures also were subjected for 90 minutes to formaldehyde gas, and the transfers 

 from them showed no growth. 



3 In experiment 7, 12 cultures were also subjected for 15 minutes and 11 cultures for 90 minutes to for- 

 maldehyde gas, and the transfers from them showed no growth. 



4 In experiment 8, 10 cultures were also subjected for 15 minutes to the gas and 10 cultures for 90 minutes. 

 None of the transfers grew. 



5 One culture contaminated. 



6 In experiment 9, 12 cultures were also subjected for 90 minutes and 11 cultures for 18^ hours to the gas. 

 There was no growth in the transfers. 



7 In experiment 10, 14 cultures were also subjected for 15 minutes to the gas, and 6 transfers grew in 16 

 days; 14 cultures also were subjected for 194 hours and the transfers from them showed no growth. 



The total absence of growth in the transfers from the cultures 

 subjected to fumigation and the abundant and vigorous growth in 



