^8 Journal of Agricultural Research voi. xvn, No. i 



Sixteen different fungi were found in these samples, including Fusa- 

 rium, Altemaria, and Colletotrichum, species of all three of which are 

 known to cause serious bean diseases. 



In all of the experiments set forth above, only a few seeds were included 

 in each sample and inasmuch as formaldehyde vapor is known to be 

 lacking in penetration it seemed desirable to try the treatment of a larger 

 quantity of seeds. 



A shipment of poppy and Cryptotaenia seed afforded an opportunity 

 to try the treatment of a larger quantity of seeds than previously had 

 been attempted. The samples used were of sufficient size to cover the 

 bottom of the dish in which the seeds were treated to a depth of three- 

 fourths of an inch. After treating the seeds a sample was taken from the 

 surface and then the seeds were carefully removed from the surface to a 

 depth of about one-half inch where another sample was taken. These 

 samples were plated out and the samples taken one-half inch below the 

 surface showed fully as many colonies of fungi and bacteria as did the 

 untreated samples while those taken from the surface showed no fungi 

 and a marked reduction in bacteria. This experiment shows the lack 

 of penetration of formaldehyde vapor. 



A comparison of the formaldehyde vapor and a 2 per cent formalin 

 solution was made. Ten different kinds of seeds were used and three 

 samples, each consisting of five seeds, of each of the different kinds of 

 seeds were made and placed in sterile petri dishes. The first set of each 

 was retained as a check; the second was treated with 2 per cent formalin 

 for 10 minutes and then washed with sterilized water twice, while the third 

 was given formaldehyde gas at the rate of 20 ounces of formalin per 1,000 

 cubic feet for 2 hours. After treatment all the plates, including the 

 checks, were poured and kept under observation for several days. In 

 all cases the 2 per cent formalin sample stood intermediate between the 

 checks and those treated with formaldehyde vapor. The vapor-treated 

 samples were remarkably free from fungi and bacteria. In fact only the 

 wheat, rice, and rye samples had any fungi present, and there was much 

 less growth in these than in the checks or in those treated with 2 per cent 

 formalin. One of the noticeable things in this experiment was that in all 

 the plates treated with the vapor there was a very marked reduction in 

 the number of bacterial colonies, as compared with the checks, while' 

 the samples treated with 2 per cent formalin showed little or no reduction 

 in the number of bacterial colonies, as compared with the checks It 

 should be stated in connection with these experiments that different lots 

 of seeds or a change in any one of the many factors concerned in all 

 probability would bring about a change in the results obtained. 



Several hundred lots of seeds have been treated wnth 20 ounces of 

 formaldehyde per 1,000 cubic feet. Subsequent plating in agar has 

 shown that molds and other fungi rarely appear in these plates if the 



