2l8 



The Cultivation of Anaerobic Organisms 



the method by connecting the tube containing the inoculated cul- 

 ture medium with a U-shaped tube, to the other end of which is 

 attached a tube to contain the pyrogallic acid solution. The ap- 

 paratus will at once be understood by a glance at the cut. The 

 mode of employing it is as follows: "After inoculating the cul- 

 ture-tube the plug is pushed in a little below the lips of the tube; 

 the ends of the U tube and the test-tubes are coated externally with 

 vaselin, the rubber tubes are adjusted on the U tube and a connec- 

 tion made with the culture-tube so that 

 the glass ends meet. One or two grams 

 of pyrogallic acid are put in the empty 

 test-tube, and packed down with a little 

 filter-paper over it; ten or twenty cubic 

 centimeters, respectively, of a lo per 

 cent, solution of sodium hydroxide are 

 then poured into the tube and the second 

 connection made before the acid and 

 alkali react to any extent." 



Wright has suggested that the cotton 

 stopper of the ordinary culture-tube 

 have its projecting part cut off and the 

 plug itself pushed down the tube for a 

 short distance. Some alkaline pyrogallic 

 acid solution is poured upon the cotton, 

 to saturate it, and the tube tightly corked. 

 Zinsser* has recommended the follow- 

 ing method as satisfactory for use with 

 Petri dishes. The dishes selected should 

 be rather deeper than ordinary. They 

 are sterilized and inoculated in the ordi- 

 nary manner and then inverted. The 

 dish is cautiously raised, and some pyro- 

 gallic acid carefully poured into the lid 

 and the dish gently dropped into place 

 again. The alkaline solution is then 

 poured into the crevice between the edges 

 of the dish and the lid, and the remain- 

 der of the space filled with melted albo- 

 lene. When these dishes are carefully 

 stood away, the alkaline pyrogallic acid absorbs all of the con- 

 tained oxygen and the anaerobic cultures develop quite well. The 

 growing colonies can be examined as often as may be necessary 

 through the bottom of the dishes, which must, of course, always be 

 kept in the inverted position. 



4. Reduction of Oxygen. — Pasteur and, later, Roux have recom- 

 mended the cultivation of anaerobic bacteria in association with 

 * "Journal of Experimental Medicine," 1906, viil, 542. 



Fig. 66. — Spirillum ru- 

 brum. Glucose agar slant 

 culture of five days. Abun- 

 dant production of pigment 

 on the surface. (The U tube 

 was soiled by the reducing 

 fluid during handling by the 

 photographer.) (Nichols 

 and Schmitter.) 



