[Vol. 6 



150 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



then filled with the above-mentioned filtrate and covered with 

 the top of a sterile Petri dish. The seeds were then removed 

 at intervals of 2, 6, 11, and 20 hours. This was done with 

 sterile forceps in the case of large seed and by means of a 

 platinum spoon with small seed. In this case it was only 

 necessary to drain the seed of the hypochlorite solution, as the 

 antiseptic action did not hinder the germination and develop- 

 ment of the seed. The transfer was made to small flasks or 

 Petri dishes (depending on the size of the seed). In these 

 flasks and Petri dishes there had been previously placed a 

 small amount of a synthetic nutrient medium 1 in 1.5 per cent 

 agar. Usually from 10 to 20 seeds were placed in each vessel. 

 The flasks and Petri dishes were then placed in an incubator 

 maintained at 25° C. The varieties of seed used in this ex- 

 periment are given in table i. Not many kinds could be tried, 

 but it will be noted that those experimented upon represent 

 seeds of widely different families. The seeds were obtained 

 from the Vaughan Seed Company, Chicago, Illinois, in all 

 cases except where note is made to the contrary. More uni- 

 formity in results was obtained when seeds were secured from 

 the same company. The results of the disinfectant are shown 

 in table I. 



According to the results indicated in the table, the commer- 

 cial " chloride of lime" was very effective for sugar beet, cu- 

 cumber, and lettuce, a higher percentage of germination and 

 more vigorous seedlings being obtained by the use of this dis- 

 infectant. The most effective time intervals are shown in 

 table iv. However, many seeds of other plants were obtained 

 free from contamination, but the effectiveness of the germi- 

 cide was not sufficiently high for practical purposes. Cer- 

 tain cucumber seed obtained from other seed companies could 

 not be sterilized even with this disinfectant. Bacteria would 

 continue to grow at the micropylar end of such of these seed as 



l The nutrient medium was made up as follows : 



Ammonium nitrate 1 gin. 



Dihydrogen potassium phosphate .5 gm. 



Magnesium sulphate .25 gm. 



Iron chloride Trace 



Can© sugar 5 grns. 



Distilled water 500 cc. 



