58 



P. M. COOK 



MEDIUM 



COOLING 

 COIL^ 



SUPPLY 



(t 



i nr ^\ 



u 



r\f 





AIR CO2 MIXTURE 



FLOWMETERS 



C^' 



THERMAL 

 WELL " 



,-^SOLENOID 

 VALVE 



PHOTO 



CELL 



CIRCUIT 



i .1 



AERATION LINE 



CULTURE OVERFLOW 

 Fig. I — Artificial light continuous culture apparatus in 4 in. column. 



assured. The aeration mixture is controlled by pressure reducers 

 and needle valves on a compressed air line and cylinders of com- 

 pressed carbon dioxide. Each gas is metered through manometer 

 flow-meters. Cotton gas filters are used, all connections are sterile, 

 and the usual aseptic techniques are employed. A photograph of 

 the apparatus is shown in Figure 2. 



