NUTRIENT MEDIA AND METHODS OF CULTIVATION. 



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sealing-wax, and the ring of putty is so placed as to include one end 

 of it, leaving a small interval at the side, or a little notch is made 

 in the putty opposite, so as to afford an exit for the gas or vapour. 



Fig. 57.— Moist Cell adapted fok Thansmission of Electricity. 



ApiMcation of Electricitij. — To study the effect of electricity 

 we may prepare a drop-culture in the moist cell. The cover- 

 glass to be used is provided with two strips of tinfoil, which are 



Via. 58. — Apparaths akkanged for Transmitting Electricity. 



isolated from the bi'ass of the microscope, and so arranged that a 

 current of electricity may be pa.ssed through them. 



A much simpler plan, which may also be emidoyed, is to take 

 an ordinary gla.ss slide and coat the surface with gold-size. The 



