102 BACTERIOLOGY. 



ized, looped platinum wire, Fig. 20. This is nothing 

 more than a piece of platinum wire of about 5 cm. 

 long, twisted into a small loop at one end and fused 

 into a bit of glass rod, which acts as a handle, at the 

 other extremity. This loop is one of the most useful 

 of bacteriological instruments, as there is hardly a 

 manipulation in the work into which it does not enter. 

 Under no conditions is it to be employed without having 



Fig. 20. 

 a 



b 

 Looped and straight platinum wires in glass handles. 



been passed through the gas-flame until quite hot ; this 

 is for the purpose of sterilization. One should form a 

 habit of never taking up one of these platinum-wire 

 needles, as they are called, for they are both looped and 

 curved or straight (Fig. 20, 6), without passing it 

 through the flame, and the sooner the beginner learns 

 to do this as a matter of reflex, the sooner does he rid 

 himself of one of the possible sources of error in his 

 work. It must be remembered, though, that it should 

 not be used when hot, otherwise the organisms taken 

 upon it are killed by the high temperature ; after steril- 

 ization in the flame one waits for a few seconds until it 

 is cool before using. 



The bit of material under consideration is transferred 

 with the sterilized loop into tube No. 1, " the original," 

 where it is carefully disintegrated by gently rubbing it 



