INOCULATION BY PLATINUM WIRES. 



59 



existing culture, the resulting growth is said to be a " sub- 

 culture" of the first. All manipulations involving the 

 transference of small portions of growth either from one 

 medium to another, as in the inoculation of tubes, or, as 

 will be seen later, to cover-glasses for microscopic examina- 

 tions, are effected by pieces of platinum wire (Nos. 24 or 

 27 Birmingham wire gauge the former being the thicker) 

 fixed in glass rods 8 inches long. Every worker should 

 have three such wires. Two are 2^ inches long, one of 

 these being straight (Fig. 14, a), and the other having a 

 loop turned upon it (Fig. 14, b). The latter is referred to 

 as the platinum "loop " or platinum "eyelet," and is used 

 for many purposes. " Taking a loopful " is a phrase con- 

 stantly used. The third wire (Fig. 14, c) ought to be 4^ 

 inches long and straight. It is used for making anaerobic 

 cultures. Cultures on a solid medium are referred to (i) 

 as "puncture" or "stab" cultures (German, Stichkultur), 

 or (2) as "stroke" cultures (Strichkultur), according as 

 they are made (i) on tubes solidified in the upright posi- 

 tion, or (2) on sloped 

 tubes. 



To inoculate say 

 one ordinary up- 

 right gelatine tube 

 from another, the 

 two tubes are held 

 in an inverted posi- 

 tion between the 

 forefinger and 

 thumb of the left 

 hand with their 

 mouths towards 

 the person holding 

 them ; the plugs 

 are twisted round 



once or twice to make sure they are not adhering to 

 the glass. The short, straight platinum wire is then heated 

 to redness from point to insertion, and 2 to 3 inches of 



FIG. 15. Another method of inoculating 

 solid tubes. 



