422 
JAMES K. WILSON 
deum vulgare, Zea mays, and 
Sinapis alba. 
monium persulfat, and bro- 
mine water. 
It will be seen from the above compilation, to which others might 
be added, that about two dozen methods have been used. Of these 
mercuric chloride, alcohol, formalin, hydrogen peroxide, or combina- 
tions of these have served in the main as the germicide. 
The writer tried various of the above methods and finding them 
unsatisfactory resorted to the use of other substances among which 
was bleaching powder (calcium hypochlorite). The favorable results 
which have been secured with bleaching powder and the many re- 
quests for the method have prompted the author to present this 
brief description. The method is simple: Ten grams of commercial 
chloride of lime (titrating 28 percent 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 percent chlorine is used as the 
disinfectant. Dilutions from this known strength may be used as 
well as the full strength. The volume of solution employed should 
be about five times or more the volume of the seed. 
In order to find the exposure at which the ability for germination 
is affected seeds were placed in sterile test tubes and covered with a 
one percent chlorine solution, obtained as above, for different lengths 
of time. Germination tests were then made with the seed which 
were removed at these different times and compared with untreated 
seed germinated In the same way. 
Seeds were also removed from the disinfecting solution at various 
intervals and tests made with respect to freedom from bacteria or 
fungus organisms. The most trustworthy tests were made by planting 
the seed on the surface of peptone agar and into bouillon. Tubes 
thus prepared were kept at room temperature, at 30° C, and 37° C. 
Observations were made on these tubes at intervals up to four weeks. 
In addition to these tests of sterility many plants which were germi- 
nated on agar were used in experimental work where sterility was 
required and was apparently maintained for several months. 
In making transfers the seed was removed from the disinfecting 
solution by means of a small hand-wrought spoon, momentarily 
drained and sown in the culture vessel. No attempt was made to 
remove completely the disinfectant from the seed since it does not 
seem to interfere with the germination unless the period of treatment 
