METHODS FOR MICROSCOPIC STUDY OF BACTERIA 241 
introduced through the surface of the medium, or after breaking the 
tubes from the side. It is, of course, necessary to sterilize the outside 
of the tube if it is to be broken. A greater degree of anaerobiosis 
may be obtained within the tubes if after sohdifying they are placed 
neck downward with the cotton plugs removed, in a beaker contain- 
ing freshly prepared alkaline p\Togallate solution.^ Growth of 
anaerobic bacteria upon the surface of agar or blood serum may be 
obtained in this manner.- Those bacteria which produce gas during 
their growth cannot be isolated in pure culture in deep agar tubes; 
the liberation of gas bubbles fragments the medium and permits the 
various colonies to coalesce. 
1 
u| 1 J. 
1 
i 
9 
i 
•s* 
Fig. 27. — Varney anaerobic culture jar. 
Varney^ has devised a very simple method for cultivating even 
the more fastidious anaerobes, utilizing phosphorus in a closed jar to 
remove the oxygen. The apparatus, dissembled, is shown in Fig. 27. 
Culture tubes, or Petri dishes are placed in the holder, a piece of filter 
paper over each of the latter. At the top, a small crucible holds a 
piece of phosphorous about ^ inch cube. This is covered with a wire 
gauze cylinder, and over all is an asbestos, or transite disc. The 
holder with its contents is lowered into the jar, which has a layer of 
water about 1 cm. deep on the bottom. The cover is clamped down 
and very soon the phosphorus burns, giving rise to anaerobic condi- 
tions very promptly. The temperature rises rapidly to about 40° C. 
under ordinary conditions. 
It is necessary to apply a coating of stop-cock lubricant to the cover 
of the jar to insure a tight joint. Also, the phosphorus should be 
dried with filter paper and not placed in the crucible until everything 
' Five grams of dry pyrogallic acid are placed in a beaker and covered with 15 to 25 
cc. of water; when dissolved a layer of kerosene or paraffin oil about 1 cm. in depth is 
added, and a 10 per cent solution of sodium hydroxide is introduced below the oil layer 
with a pipette. 
2 Rickards: Centralbl. f. Bakteriol., orig., 1904, 36, 557. 
3 Jour. Lab. and Clin. Med., 1926, 11, No. 12. 
16 
