The Laboratory 11 



tant that even the room used for routine stock 

 cultures be air-conditioned, with faciilties for 

 cooling in extremely hot weather. Cultures main- 

 tained in an ordinary laboratory room without 

 such control show a marked seasonal variation in 

 growth rate (Fig. 26) (White, 1937, 265) and 

 may, in extreme weather, suffer serious injury. 

 The experimental culture room should be pro- 

 vided with plenty of table space or, alternatively, 

 with table-height wall benches, since most experi- 

 mental cultures must be examined at frequent 

 intervals and must be easily accessible. Stock 

 cultures can be kept on shelves, since they do not 

 need to be handled. 



The laboratory. Like the culture room, the 

 laboratory must be adapted for the particular 

 type of problem in view. A complete laboratory 

 should contain facilities for chemical analyses, a 

 good hood, balances, drying ovens, equipment for 

 preparation of sections and slides and their ex- 

 amination, equipment for special types of experi- 

 ments such as respiration apparatus, facilities for 

 glass-blowing, etc. Gas outlets for use in connec- 

 tion with plant tissue culture work should, where 

 possible, be restricted to this room and the media 

 room. There should, of course, be adequate cup- 

 board space for chemicals. 



The office. Every man has his own ideas of 



