THIELWTOPSrS PARADOX A. 



547 



iiuinial spores round it from germinating. From tlie appear- 

 ance of tho developing cultures, it would seem that a large 

 proportion of Thidaviopsis spores germinated even in the 

 strongest solution in which they germinated at all, but this 

 point was not tested by observations in hanging drops, as the 

 behaviour of the spores is not the same under the latter 

 conditions. 



In the following tables tlie first column gives the date of 

 instituting the cultures and the percentage of the chemical 

 in tlxern ; the others record the observed growth. The 

 control culture was made with cane extract only. Where the 

 growth is said to be good, the culture had reached the macro - 

 conidial stage and covered the surface of the liquid. 



Potassium Nitrate. 



Dec. 27. 



Per- 

 centage. 



Dec. 29. 



Dec. 30. 



Dec. 31. 



Per- 

 centage. 



Jan. 2. 



Jan. 4. 



10 



1-5 

 20 

 2-6 



3-0 



Control 



All growing 



well. ^ 



Macroconidia ,' 

 forming. 



Good. 



Good 



growth 



in all. 



6-0 

 6-5 



Growth 



beginning 



in all. 



Good. 



Good 

 do. 

 do. 

 do. 

 do. 

 do. 

 do. 

 do. 

 do. 



Jan. o. 



Per- 

 centage. 



Jan. 8. 



Jan. 9. 



Jan. 11. 



10 Growth i Fair growth; | Good growth. 



beginning, macrospores. 



12 Do. Poorgi'owth; Poor growth; macrospores. 



macrospores. 



14 Do. do. I do. 



16 Nothing. Mycelium only.' Poor growth; only one 



I small patch of spores. 



18 Do. Nothing. i Nothing up to January 14. 



20 ' Do. do. I do. 



Control Good, i 



Penicillium subsequently developed in the 12 and 14 per 

 cent, cultures. 



