386 Journal of Agricultural Research voi. xix, no. s 



The best control in this experiment was obtained with a presoak of 5 

 hours, followed by 30 minutes' formalin soak, then covering i hour. 

 Such a process, requiring 6^ hours in all, would be particularl)^ desirable 

 because of the ease in subsequently drying the seeds by spreading them 

 in the sun on the day of treatment, Further field repetition of this 

 experiment, which was suspended at this time by the advent of winter, 



PERCENTAGE OF GERMINATION 



40 50 60 70 80 90 



Fig. 8.— Graph showing effect of formalin i to 320 and i to 200 on germination of corn, barley, and oats 

 with and without presoaking: A, controls ; B, seeds soaked in formalin i to 320 for 10 minutes, drained, 

 kept moist (covered) 6 hours, dried overnight, and planted; C, seeds soaked in water lominutes, drained, 

 and kept moist (covered) 6 hours, then soaked in formalin i to 320 for 10 minutes, drained, and kept moist 

 (covered) 6 hours, dried overnight, and planted; D and G, controls; E and H, seeds soaked in formalin 

 I to 20ofor lominutes, drained, kept moist (covered) 4 hours, dried overnight, and planted; F, seeds soaked 

 in water 10 minutes, drained, kept moist (covered) 10 hours, then soaked in formalin i to 200 for 10 

 minutes, drained, kept moist (covered) 4 hours, dried overnight, and planted; I, seeds soaked in water 

 lohours, drained thoroughly a few minutes, then soaked in formalin i to 200 for 10 minutes, drained, 

 kept moist (covered) 4 hours, dried overnight, and planted. Records of the germination were made 

 on the fifth and seventh days after planting in the greenhouse.. 



is necessary, however, before definite recommendations on this modifi- 

 cation can be made. 



EFFECT OF THE PRESOAK METHOD ON OTHER CEREAI^S 



The uniform results obtained on nine different varieties of wheat by 

 the presoak method of treatment with formalin and copper sulphate and 

 a consideration of the underlying principles governing its salutary action, 

 as will be discussed later, suggested that it might be generalized for the 

 treatment of all seed-transmitted diseases of economic importance amen- 



