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 
a 
Fic. 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 :— 
1. The pus. 
2. A sloped agar tube and a stab gelatin tube. 
