AGf~ICULTURAL RESEARCH, PUSA.

130 PRACTICAL BACTERIOLOGY
tubes are firmly held at their lower CllJ.!:l between the
thumb and first two fingers of the left hand, with the
sloped surface of the medium towards the worker.
The tube containing the growth should he on the left
and the uninoculated tube on the right. With the
right hand loosen the cotton-wool stoppers by rotating
them in the mouths of the tubes so that they may be
removed easily. Take the holder or the inoculating
wire at its end between the thumb and first two
fmgers of the right hand (as in holding a pen). Sterilise
the wire by holding it vertically in the Bunsen flame.
Remove the stopper of the tube from which the inoculation
is to be made with the crooked third finger of
the l'ight hand, and flame the mouth of the tube. Pass
the needle into the tube and touch a portion of the
medium free from growth to ascertain if the needle is
sufficiently cool. If too hot, the wire will melt thc
agar, causing a furrow, and might of course kill the
organisms in removing the growth. When. the wire is
cool, the growth is scraped from thc surface, care being
taken not to wound the agar. Withdraw the wire,
remove the stopper from the other tube with thc
crooked little finger and flame the mouth of the tube.
Insert the wire charged with the growth and lightly
smear the surface of the agar. Withdraw thc wire
and sterilise it, flame the mouths of the tubes and
replace the stoppers. The nature of the inoculated
material and also the date should be written on the
tube by means of a grease pencil, or on a gummed
label which is then affixed to the tubc. .
With stab cultures, the tubes arc held similarly and
the straight wire charged with bacterial growth is
plunged into the centre of the medium, carc being
taken to withdraw the wire in the same line, and not
to cause splitting of the medium.
In inoculating a fluid medium, such as broth, from
a solid culture, the tube should be inclincd almost to
the horizontal and the growth on the loop deposited
on the wall of the tube just above the surface of the
liquid at the lower end of the tube. On returning