BACTERIOLOGY 



O 



poses is No. 28, English standard gauge, diameter .014 inch. 

 The wire may be straight throughout its length, or the tip may 

 be bent to form a loop (German, Oese). It is well to follow, from 

 the beginning, certain rules which make the use of the platinum 

 wire safe and accurate. Every time it is taken into the hand 

 and before using it for any manipulation, heat it 

 in the flame of a Bunsen burner or an alcohol lamp 

 to a red heat; and always, after using and before 

 putting it down, heat it again to a red heat. After 

 the needle has become wet by dipping it in a fluid 

 and is to be sterilized in the flame, it is necessary 

 to avoid " sputtering" of the fluid by bringing the 

 wet needle gradually to the flame, so as to dry the 

 material adhering to it before burning it. This 

 procedure must be done with great care when the 

 wire has been dipped in milk or other substances 

 containing oil. When the needle " sputters," as 

 it is called, from too rapid heating, particles that 

 have not yet been sterilized may be thrown some 

 distance. On no account should the needle touch 

 any object other than that which it is intended it 

 should touch. With such a platinum wire, which 

 has been properly sterilized, one can easily remove 

 portions from a culture of bacteria, or from a 

 fluid in which bacteria are supposed to be present. 

 The glass rod in which the platinum wire is fixed 

 should be held between the thumb and forefinger of the right 

 hand like a pen. 



- Glass Pipettes. Sterile glass tubes drawn out to form slender 

 capillaries, Pasteur pipettes, are very convenient instruments 

 for handling bacteriological materials, and, for many kinds 

 of work, really indispensible. They serve nearly all the pur- 

 poses of the platinum wire and are capable further of use to 

 transfer large quantities of fluid without contamination. They 

 are also especially useful in collecting material from patients 



FIG. 20. Need- 

 les used for inocu- 

 lating media. 



