2l8 



Journal of Agricultural Research 



Vol. XX, No. 3 



stand an immersion of 8 hours without injury. It can remain i hour 

 without injury in a solution twice as strong. Table V shows the result 

 of an experiment to determine the resistance of Little Club wheat to 

 long exposures to various strengths of formaldehyde solutions. 



Table V. — Relation between strength of solution, duration of exposure, and seed injury 



Table V shows that Little Club wheat, thrashed with little injury, will 

 stand an 8-hour exposure to ao.i per cent solution., a i-hour exposure to 

 a 0.2 per cent solution, or a 20-minute exposure to 0.45 per cent and 4.5 

 per cent solutions. 



The post-treatment injury from dry storage after subjection to a 0.1 

 per cent solution as well as to stronger ones has been demonstrated not 

 only with Little Club and Early Baart wheat but with Sonora, Marquis, 

 Defiance, and White Australian. 



PHYSICAL PROPERTIES OF 



FORMALDEHYDE AND PARAFORMALDE- 

 HYDE 



After the fact had been established that a 0.1 per cent solution is 

 innocuous but that the drying of this solution on the seed is harmful, the 

 next step was to investigate the physical and chemical properties of formal- 

 dehyde in order to find a cause for the injury and a means of avoiding it. 

 The natural supposition was that the injury is due either to a concentra- 

 tion of the solution on the seeds as they dry or to a coating of paraformal- 

 maldehyde left upon them as the solution evaporates. It seemed at first 

 inexplicable, however, that the seeds stored damp, or even wet, should 

 remain absolutely uninjured indefinitely. In an effort to connect these 

 facts with the possible persistence and disappearance of the chemical on 

 the seed some qualitative tests for formaldehyde in washings of the 

 damp and dried seed were undertaken. It was the result of these first 

 qualitative tests which led to the intensive study of the behavior of 

 formaldehyde solution and paraformaldehyde and the possible determina- 

 tion of the cause of seed injury reported in this paper. 



