viii SEPARATION OF TETANUS BACILLI 119 



half an hour to one hour, as above described. This should 

 be repeated, until the cultures are pure. 



The separation of tetanus bacilli without animal 

 inoculations is by no means easy. 



The gelatine cultures when pure may be kept in the 

 cool incubator. 



To keep the tubes at a steady temperature of 60 C. 

 arrange a large beaker, filled with water, over a 

 gas flame, and regulate the temperature by means 

 of a thermo-regulator, as shown in the diagram 

 (Fig. 13). 



