FORMALIN TREATMENT FOR OAT SMUT * 607 



Table XV. Formaldehyde Vapor Applied Without Return Cubbent. 



Table XVI. Formaldehyde Vapor Applied With Returx Current. 



Length of 

 Treatment 



Length 

 of Row 



Date of 

 Seeding 



Total No. 

 of Heads 



No. of Per cent 



Heads of Heads 



Smutted Smutted 



Results of these trials indicate that the grain exposed to 

 formaldehyde vapor without the return current was only slight- 

 ly disinfected when compared with the check. The return 

 vapor current at room temperature proved much more efficient 

 as indicated by the declining percentage of smut in the treated 

 plots. 



It has been observed that temperature has more or less in- 

 fluence on the efficiency of formalin fumes. Some investigators 

 recommend the use of warm water in the ordinary solution 

 treatments. 



Wheeler also conducted a scries of experiments to determine 

 this factor and its relation to the gas treatment. (See Table 

 XVII.) Rossnan states that temperature is an importanl fac 

 tor in disinfect inn- with formaldehyde. The gas condenses at 

 20 degrees C. to the solid polymeric paraform and disinfection 

 should never be attempted if the temperature is under 10 de- 

 grees C. The action of the gas seems to be about the same be- 

 tween the temperature of 10 degrees C. and 27 degrees C. 



