34 



Journal of Agricultural Research 



Vol. XVII. No. I 



The pathological inspectors of the Federal Horticultural Board have 

 treated several hundred lots of seeds each year in the liquid treatments 

 commonly recommended and have found the formaldehyde solutions 

 the best for the greatest number of cases. Formaldehyde is also known 

 to be a very efficient germicide when used in the form of a vapor as a 

 disinfectant for contagious human diseases. 



For the above reasons formaldehyde vapor has been selected for this 



work. 



APPARATUS 



A galvanized iron can (fig. i, A) having a capacity of approximately 

 130,000 cc. was used. After introducing the seeds and organisms. 



Fig. I— Formaldehyde-vapor disinfecting apparatus 



Steam was added through a rubber tube (B) from an autoclave (C). 

 The formaldehyde solution (Shoemaker and Busch, U. S. P. VIII, 40 

 per cent by volume of formic aldehyde) was diluted one to one with 

 water to give a greater volume of liquid. This formaldehyde solution 

 was introduced through an atomizer (D) with the aid of compressed air 

 (F), the nozzle of the atomizer being inserted in the rubber tube (B), 

 through which the steam passes as it enters the can. This insertion 

 was made as close to the can as possible. Steam was first introduced 

 and then the compressed-air tube was attached to the atomizer and the 

 formaldehyde solution was forced in while the steam was still entering. 



