MICHIGAN ACADEMY OF SCIENCE. 191 



Brown (1) has further shown that sulfuric acid and copper sul- 

 fate were unable to i)euetrate as far into Barley seeds as mercuric 

 chloride, and attributed this to ia "selective action" of the seed coat; 

 hence this method mioht not injure the youu"^ seedlinj»s as much. 



Lipman and Fowler (3) sterilized seeds of Vicia sicula by plac- 

 ing; them in 1 :1.0nO mercuric chloride solution for twenty minutes, 

 then i-insin<; in sterile water and treatinf»- with sulfuric aci*! for 

 twenty minutes to aid <»ernynation and take off the mercuric 

 chloride. 



Selby and Manns (5) found that the treatment most practical in 

 sterilizing seeds containing internal infection in work on wheat was 

 to soak the kernels eight to ten hours in water and then immerse 

 one to two minutes in alcohol (50%) containing two grams of mer- 

 curic chloride in each 1000 cc. This solution poured off and the 

 seeds covered with 03% alcohol (absolute alcohol is less liable to 

 contain germinable spores) to remove traces of the fungicide. As 

 far as showing internal infection, the above method is reliable only 

 for those organisms which manifest their presence by growth on 

 agar or through injury to the plantlets. 



Experiments. I found as above stated that the mercuric chloride 

 1 ■')(){> was injurious to my young seedlings when the seeds were 

 treated for twenty minutes ; I made some trials with lower con- 

 centrations and for shorter time of treatment, but still found it 

 injui'ious to the young seedlings. My next method was to try sul- 

 furic acid (sp. gr. 1.S4) for different lengths of time. After a few 

 preliminary tests I found that if the seeds were treated for three 

 to four minutes with concentrated acid that jn^actically all of the 

 seeds remain sterile; only one occasionally showed infection and 

 this after some time, showing probably that the infection was deep 

 in the seed coats and is not reached by the disinfectant. 



I also tried dipping the seeds in alcohol and then burning this 

 alcohol off, but this treatment killed all of the seeds, so would be of 

 no use in sterilizing poj) corn seeds, 



I next made an exjieriment following the suggestions made by 

 Lijunan and Fowler (3). First ])lacing the seeds in a solution of 

 mercuric chloride 1:1000 and then in sulfuric acid (sp. gr. 1.84) 

 and the results will be seen in the accompanying table : 



