30 



Killing of Botrytts Spores hy Phenol 



until the period of 80-100 minutes is reached. During this interval 

 nearly 30 per cent, of the total number of spores are killed. Thereafter 

 fewer and fewer are killed in each time-interval, until in the 160-180 

 minutes interval only about 1 per cent, die; and the last survivor would 

 not succumb until some four hours or more had elapsed from the be- 

 ginning of the experiment. The whole curve, which may be called a 

 survivor curve, has a sigmoid shape (see Fig. 1). 



In Tables II, III and IV are given experiments with higher amounts 

 of phenol, viz. 0-5, 0-6 and 0-7 per cent., and three of these are also 

 plotted in Fig. 1. The close scale of the figure somewhat obscures the 

 character of the curves with the higher strengths, but if plotted on a 

 more open scale they will be seen to conform to the general type of the 

 04 and 0-5 per cent, curves. 



Table II. 18. 9. 19. 27 day spores. 

 200,000. 25-2°. Phenol 0-5 per 

 cent. Control: 89-5 per cent, of 

 777 spores germinated. 



Table III. 30. 10. 19. Phenol 0-G 

 percent. 34 day spores. 280,000. 

 Control: 83-88 per cent, germi- 

 nated in 515. 24-8°. 



Per cent, 

 germinated 



100 

 95-3 

 93-3 



76G 



66-6 



45-3 



16-8 



13-8 



■lis 



0-84 



0-:39 



After 39 mins. two spores only germi- 

 nated; after 42, 45 and 48 mins. none; 

 after 51 mins. one; and after 54 mins. 

 none. 



Table IV. 1. 10. 19. Phenol 0-7 per cent. 18 day spores. 25°. 

 Control: 86-95 per cent, of 914 spores germinated. 



