the sides by a large mass of waters Lirht was excluded. 



The air of the chamber and the water arcund it, .vers kept in 

 constant rotation by mechanical stirrers. The seven chambers 

 were built in a row with the water' jacket of cne in cpnte 

 with that of the next, excepting for a sheet-iron parti t 

 which kept the several masses of water entirely distinct. 

 A tank of mechanically stirred water having automatic tempera- 

 ture control was added at either end c^ the eeries of experi- 

 ment chambers, and the entire apparatus was well insulated 

 from the surroundinp-s. The two ends of the series were ad- 

 justed f or any two desired temperatures. Between these, after 

 equilibrium had been established, lay the maintained tempera- 

 tures to be studied, eech of which differed from the next by 

 a certain amount depending on the posir.ion of the chamber as- 

 suming it, in the series. The daily fluctuations were only 

 rarely more than .50. Access to the chambers was had f^cm 

 above, and cf course, the maintained temperature of the cul- 

 tures was mere or less disturbed when the chambers were open- 

 ed for ar instant to take out a group of them f o - measurement. 



STRUCTURAL DIFraREITCES 



RtfLATHTJ TO TEMPWRATUHK 



Microscopic observation of the fungus hyphae rear the 

 margin of the mycelial disk was nads occasionally at the time 

 the measurements were carried out. No spores were produced 

 in any cf the experimental cultures, so that vegetative grc 

 alone can he considered. The only structural dir J 'c: ences e - 

 served between different cultures of t>e same fungus consi ? 

 i n more or leas marked peculiarities in cultures that had 



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