2 1 o Journal of A gricultural Research vol. xx, No. 3 



be helpful in any consideration of the more practical problems con- 

 nected with the use of this chemical as a fungicide. 



Certain investigators working on this problem have shown that 

 injury to formaldehyde-treated seed occurs when the seed is allowed 

 to dry after treatment. The earliest report we have found of such 

 work is that of McAlpine (u), 1 whose experiments showed that seed 

 treated with a solution of i pound of formaldehyde in 40 gallons of 

 water just prior to sowing under conditions favoring immediate germi- 

 nation grew as well as untreated seed. If, however, the seed was 

 allowed to dry for a day or more before germinating or if it remained 

 in dry soil some days before a rain, it suffered extreme injury. He 

 gives instances of such injury reported by farmers who from experience 

 had learned to sow formaldehyde-treated seed in moist soil immediately 

 after treating. McAlpine attributed this injury to the hardening effect 

 of formaldehyde on the seed coat. He claimed that by soaking the 

 dried treated seed in water prior to sowing this injury was averted. 

 He further stated that the injury after a dip in a 1 to 40 solution was 

 most pronounced when the seed had been kept a week after treatment. 

 After two weeks it began to improve until, when sown a month after 

 treatment, it was practically as good as 24 hours after treatment. He 

 stated also that this recovery did not occur when the solution used 

 was twice as concentrated. 



In 1908, Shutt (14) found that a delay of three days in sowing after 

 the formaldehyde treatment reduced the percentage of germination and 

 increased the proportion of weak and slender plants. In opposition to 

 this are the results reported by Hurst (8), who states that seed may be — 



treated and kept for any reasonable length of time without affecting its vitality. 



Some of his samples, he says, had been treated 12 months before and ger- 

 minated as well as the untreated seed. Stewart and Stephens (16) 

 found that after the use of a 1 to 50 solution their samples were uninjured 

 by 6 weeks' dry storage, which was the longest storage period tested. 

 Brittlebank (3) noted a falling off in the germination of seed treated with 

 formaldehyde solution after being kept dry a week, the decrease contin- 

 uing to the sixth week, after which the percentages rose and fell with 

 various fluctuations through the remainder of the 54 weeks. Giissow 

 (6, p. 21-22) reported some figures obtained by Dr. C. H. Saunders, 

 Dominion Cerealist, showing that treated seed which originally germinated 

 75 per cent was entirely killed after being stored dry a year. Some barley 

 and oats treated similarly were almost wholly killed after standing 

 dry a year. 



The first investigators to connect this storage injury with that property 

 of formaldehyde by virtue of which it forms a solid condensation product 

 or polymer upon evaporation were Darnell-Smith and Carne (5), who 



1 Reference is made by number (italic) to " Literature cited," p. 243-244. 



