210 Cultures, and their Study 



Heavy wires used for securing diseased tissue from animals 

 may be flattened at the ends by hammering, and may thus 

 be fashioned into miniature knives, scrapers, harpoons, etc., 

 as desired. 



Ravenel has invented a convenient form for carrying in 

 the pocket. It consists of the platinum wire fastened in a 

 heavier aluminium wire which in turn fits into a piece of 

 glass tubing. When carried in the pocket, the position of 



Fig. 37- Platinum needles for transferring bacteria; made from 

 No. 27 platinum wire inserted in glass rods. 



the platinum wire is reversed in the glass tubing and pro- 

 tected by it (Fig. 38). 



Immediately before and immediately after use, the platinum 

 wire is to be sterilized by heating to incandescence in a flame, 

 in order that it convey nothing undesirable into the culture, 

 and in order that it scatter no micro-organisms about the 

 laboratory. 



Capillary glass tubes are employed by the French for 

 many of the manipulations. They are made of J- or f-inch 

 glass tubing cut into 25 cm. lengths, heated at the center, 



Fig. 38. Platinum wires for bacteriologic use. 



and drawn out to capillary ends about 5 cm. long. They 

 are sealed at one end and plugged with cotton at the other, 

 and a number of them, prepared at the same time, sterilized 

 (Fig. 39). They can be used for all the purposes for which 

 the platinum wire is employed, and in addition can be used 

 as containers for small quantities of fluids sealed in them. 

 When about to use such a tube, its sealed capillary end 

 should be broken off with forceps, and the tube sterilized 

 by flaming. 



Technic of Culture Manipulation. In order that ac- 

 curate results may accrue from the employment of culture 



