l6 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



INOCULATION OF CULTURE MEDIA 



The method in which this is done varies greatly according to 

 the end in view, and variations of the process now to be described 

 will be mentioned under their appropriate headings. We will 

 suppose that we have to examine a specimen of pus, and wish to 

 make a stroke culture on agar and a stab culture in gelatin. The 

 following must be at hand : 



1. The pus. 



2. A sloped agar tube and a stab gelatin tube. 



3. A Bunsen burner or a spirit-lamp with a tall flame. 



4. A pair of dissecting forceps. 



5. Platinum needles. Each needle consists of a piece of 

 platinum wire about 3 inches long mounted in the axis of a glass 



Fig. 8. — Platinum Needles. 



rod about 6 or 8 inches in length. The wire should be just thick 

 enough not to bend too easily. They are easily prepared. The 

 rod is selected, and the length of platinum wire is held in an 

 ordinary pair of forceps. The end of the glass rod is held in the 

 flame until quite soft ; the end of the wire is then heated to 

 redness, and pushed into the rod to the depth of about J inch, 

 taking care that it is kept in the axis. The whole is allowed 

 to cool, and is ready for use. 



For some purposes we use needles which terminate in a small 

 loop, so that they will retain a drop of fluid. These are prepared 

 in the same way as the straight needles, the free end of the wire 

 being subsequently twisted round a French nail or other suitable 

 object. 



The method is as follows : 



I. Hold the culture-tube you are going to inoculate first between 

 the index and middle fingers of the left hand, pointing the mouth 



