1919 



Gail; on Fncus and Hiidrorjeii Ion 



295 



Table 2. Percentage of germination in different pH values and temper- 

 atures of water. 



1. The higher percent of germination occurs in seawater having 

 pH values above 7.4 and below 8.6 in all temperatures considered. The 

 maximum germination occurs in seawater having pH values between 8.0 

 and 8.2. 



2. The per cent of germination usually diminishes above a tem- 

 perature of 17°C. 



3. A microscopic examination of the oosjDores in seawater having pH 

 values above 8.2 with a temperature above 24°C showed that the cell 

 v/all and plasma membrane were ruptured and that the protoplasm was 

 exuding. 



Permeability of oospores 



Experiments were now made to determine whether permeability is 

 related to inhibition of germination of oospores and to the death of 

 oospores in different pH values of seawater. Oospores were secured in 

 the usual manner. These were stained one to three hours in a weak 

 neutral red solution. Watch glasses were washed in seawater and rinsed 

 thoroly with seawater having the pH value that was to be used in that 

 particular watch glass. The watch glass was then labeled with the 

 correct pH value. Watch glasses for each pH value used were treated 

 in the same manner. A large number of stained oospores were now 

 placed in each watch glass by means of a medicine dropper. The medi- 

 cine dropper was also used to place seawater having correct pH values 

 on the stained oospores. The water on the oospores was changed four 

 times. This was done to make certain that the correct pH value was in 

 each glass, as the oospores were stained in seawater having a pH value 

 of 8.2. 



During the first attempts the oospores were examined every 15 

 minutes under a compound microscope to observe any change. As no 



