APPENDIX D 

 THE INOCULATING CHAMBER 



In every laboratory where much careful work is to be done an in- 

 oculating chamber is necessary. This is usually a closet large enough 

 for a pel-son to enter, although chambers are also made into which the 

 operator thrusts only his arms. The closet type (Fig. 19) is usually 

 preferred. It is 4 or 5 ft. square and at least 7 ft. high. One or 

 two windows should be provided, to give plenty of light. The door 

 should lit tightly and be provided with a spring which will keep it 

 closed. The interior of the closet should be lined with some mate- 

 rial which can be easily cleansed with a damp cloth ; linoleum serves 

 the purpose well. Xear the top of the closet the wall should have an 

 opening for ventilation. A hole 15 in. square may be fitted with 

 a frame which is covered with a fine wire screen and one or two 

 thicknesses of cheesecloth or a thin layer of absorbent cotton. This 

 filtering layer of cloth or cotton should be renewed frequently, as 

 it becomes filled with dust. 



Before making inoculations in the closet, the walls, floor, ceiling, 

 and shelf should be wiped with a cloth wrung out of 1 : 1000 solu- 

 tion of mercuric bicloride solution (for method of preparation see 

 Exercise 132), or 3 per cent formalin. 



The inoculating closet is not a good place to store stock cultures. 

 The only shelf it should contain is the work shelf, on which there 

 should be a gas burner for sterilizing the inoculating needles. 



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