[Vol. 10 



154 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



amounts of 0.5766N H,PO, or 0.1005N KOH to 25 cc. of the 

 nutrient solution. Approximately 4 cc. of each adjusted solution 

 was placed in a clean test-tube, and to each of these was added 

 0.1 cc. of a heavy spore suspension in distilled water. The 

 addition of this amount of spore suspension produced no change 

 of reaction between P H 3.1 and 8.3 inclusive, and only very in- 

 considerable change outside these bounds. Germinations were 

 made in hanging drops, or Van Tieghem cells, and due precautions 



Fig. 10. 



were observed relative to the cleanliness of the slides, rings, and 

 cover-glasses. By use of a platinum loop small drops of the spore 

 suspension were transferred to cover slips, and these were in 

 turn sealed over the glass rings by means of petrolatum. The 

 platinum loop was flamed and cooled before being used on each 

 solution. Several drops of the appropriate solution were placed 

 in the bottom of each cell. Duplicate cells were prepared for 

 each solution of a different Ph value. These were maintained at 

 a temperature of 25° C. during the germination period. At 

 the end of 22 hours, the amount of germination was determined 

 by taking the average of the counts of 10 different fields, a total 

 of 200-300 spores being involved in each average. 



