74 Plant Tissue Culture 



sions to hold forty 125 ml. Erlenmeyer flasks, and 

 three such trays of flasks can be placed simul- 

 taneously in a 20-inch autoclave. Shelves should 

 be provided of proper depth to hold these trays 

 where nutrient can be stored after sterilization. 



The transfer room. This is perhaps the most 

 important room in the laboratory. A good trans- 

 fer room is absolutely essential for satisfactory 

 tissue culture work. For very simple manipula- 

 tions, a low bacteriologist's hood may suffice, but 

 for any extensive work a special room is essential, 

 and, since the conditions required differ somewhat 

 from those in a pathological laboratory, it should, 

 if possible, be reserved for this work alone. Rob- 

 bins, and Lewis use plywood chambers about 

 4'6" X 5'6" X 7'6", provided with air filters, elec- 

 tricity, and gas. The ideal transfer room should 

 be an inside room, without windows. Windows 

 always leak, no matter how well built, so that a 

 marked increase in contaminations in a room pro- 

 vided with them always occurs in windy weather. 

 Light from windows is also very irregular. The 

 temperature drop across a window, moreover, sets 

 up convection currents within the room. These 

 annoyances are eliminated by using an inside 

 room. It should have no special heating unit, 

 since such a unit is also a source of convection 

 currents. A well designed air-conditioning outfit 



