1919] 



YOUNG SEED DISINFECTION 149 



of grains for smuts, using formaldehyde as the disinfectant. 

 They found that wheat seed high in moisture content absorbed 

 the formaldehyde vapor very rapidly and were materially in- 

 jured. Many other examples might be cited which, up to the 

 present time, have seemed to indicate that no one germicide 

 can disinfect under all conditions. 



In his studies on the comparative viability of seed, fungi, 

 and bacteria, de Zeeuw ( '12) was unable by the usual method 

 to free seeds of a certain amount of the disinfecting agent. 

 He believed that the adherence of the agent permitted the con- 

 tinuance of antiseptic action, leading to a false sense of se- 

 curity at the time of making the transfer of the young seedling. 

 He therefore devised a special apparatus by which it was pos- 

 sible to wash the seed thoroughly in order to free it from the 

 germicide, and at the same time it prevented possible contami- 

 nation from the outside during treatment. 



The object of this work is to determine the effectiveness of 

 some of the well-known disinfectants in relation to particular 

 groups of seeds. No new methods have been devised nor new 

 germicides used. In all cases the antiseptic action (that is, 

 antiseptic action due to incomplete washing) of the disin- 

 fectant was prevented only when it hindered normal germina- 

 tion and growth of the seed. The percentage of germination 

 and appearance of growth were the indicators in each experi- 

 ment. 



The first germicide employed in this work was commercial 

 chloride of lime (largely calcium hypochlorite), as suggested 

 by Wilson ('15), and his method was followed, namely, "Ten 

 grams of commercial chloride of lime (titrating 28 per cent 

 chlorine) is mixed with 140 cc. of water. The mixture is then 

 allowed to settle for five or ten minutes and the supernatant 

 liquid decanted off or filtered. The solution or filtrate, which 

 contains about 2 per cent chlorine, is used as the disinfectant. 

 The volume of the solution employed should be about five 

 times or more the volume of the seed. ' ' 



The seeds were placed in glass tumblers, in quantity not to 

 exceed about one-fifth of the final volume. The tumblers were 



