

Tvia data of table VII indicate tha J | I 



ature ranges are not the san.e for all four fungi, a v for 



two oi , Pythiac; tie and Phytophthora, it is not the sa 



for all e^pcsure periods even of the same fungus. 



Since the consecutive temperature actually tested were 

 rqther far apart, in all cases, these observed optical tewpera- 

 ture valves do net necessarily r the medium points 



respective optimal range, and they stand for these ranges 

 only in a very rough and general way. In order to study 



these differences "between the fungi ard to "bring out the rela- 

 tion that holds "between the ape of the culture and its growth 

 rate, th r rates for the consecutive days of the exposure 



period must v e employed. 



MEAN RATES FOR SUCCESSIVE OBSERVATION 



PERIODS IN THE EXPOSURE PERIOD. 



Introducto ry : If the mean 24-hour rate of enl&rrs- 



ment for the same fungus, with a maintained tempera- 



ture, is different for different lengths of exposure period, 



this must of course v e due to progressive alteration of the 

 instantaneous rate with the lapse of time fro beginni 



of the culture. This makes it desirable to study the march 



of t stantaneouB rats value throughout th 3 pericd cf expo- 



sure, and this is rest done by resorting to graphs. each 



of the four funri a grevvth-temperaturs graph, was prepared to 

 represent each one of the successive 24-hc- -srvatior. periods 



( ithin ths exposure period) for which ad>r data were 



avai lab] \ . 



