22 BACTERIOLOGICAL DIAGNOSIS. 



Then cut each cylinder in half by a cut running 

 obliquely from end to end; the shape of each half 

 should be exactly like that of the medium in a sloped 

 gelatin tube. Place the halves in a large vessel of 

 tap-water and allow them to soak all night ; it is a good 

 plan to use running water if possible. 



After this has been done place each half (base 

 downwards) in a test-tube, having previously inserted 

 a small mass of absorbent cotton-wool and enough 

 water to saturate it. Plug the mouth of the tube with 

 cotton-wool and sterilise on three successive days. 



INOCULATION OF CULTURE MEDIA. 



The method in which this is done varies greatly 

 according to the end in view, and variations of the 



FIG. 8. Platinum Needles. 



process now to be described will he mentioned under 

 their appropriate headings. We will suppose that we 

 have to examine a specimen of pus, and wish to make 

 a stroke-culture of agar and a stab-culture in gelatin. 

 The following must be at hand : 



i.- The pus. 



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



