WRIGHT'S METHOD FOR ANAEROBIC CULTURES 155 



number of tubes or Petri dishes inoculated with anaerobic germs are 

 to be treated by the pyrogallic-acid method, anatomical jars may be 

 used for the pupose. Tubes can be placed in a slanting position 

 against the wall of the jar, but when Petri dishes are used some device 

 for them to rest upon should be placed in the bottom. The chemicals 

 are placed in the jar, its lid screwed down and sealed with paraffin, 

 and the jar is then ready to go into the incubator. A more elaborate 

 glass jar is one made with shelves on which the plates containing the 

 cultures may rest. This can be used with either the hydrogen or the 

 pyrogallic-acid absorption method. 



Anaerobic Cultures in Hen's Eggs. Anaerobic cultures may also be 

 raised in hen's eggs. The latter should be fresh and the shell must 

 be cleansed externally by washing in a bichlorid solution and sub- 

 sequently in sterile water, and finally drying with sterile cotton. A 

 suitable spot is then perforated with a sterile needle and the inocu- 

 lation is made with a slender platinum needle. The small hole is 

 then closed with hot sealing wax and the whole outer surface coated 

 with a varnish. Eggs so prepared are then incubated and at the 

 proper time broken and their contents discharged into a sterile glass 

 receptacle for microscopic examination. 



The preparation of anaerobic cultures by the removal of the air 

 from the container of the culture medium by an air pump is not often 

 practised nowadays, since other anaerobic methods are much simpler 

 and more preferable. 



Wright's Method for Anaerobic Cultures. Wright has devised two 

 methods of developing anaerobic cultures: one of them is a modifi- 

 cation of the pyrogallic-acid method of Buchner, the other consists 

 in removing all air from the fluid culture medium by a special arrange- 

 ment of the glass tube which contains the medium. These methods 

 are described in Mallory and Wright's Manual of Pathological 

 Technique. The first method is applicable to cultures in test-tubes 

 and flasks; the details are as follows: 



After the culture medium in the test-tube has been inoculated the 

 cotton stopper is pushed into the test-tube, so that the top is about 

 1.5 cm. below the mouth of the test-tube. It is usually desirable to 

 cut off a part of the protruding portion of the cotton before doing 

 this. This cotton of the stopper should be of a kind that will readily 

 absorb fluids. Now fill the space in the tube above the cotton stopper 

 with dry pyrogallic acid and quickly add enough of a strong watery 

 solution of sodium hydrate to dissolve it all. Avoid pouring on an 

 excess; for a test-tube f inch in diameter about 2 c.c. will be ample. 

 Then, as quickly as possible, insert a rubber stopper firmly in the 

 mouth of the tube so as to close it tightly. The culture is then ready 

 to be set aside for development. The solution of sodium hydrate 

 used consists of one part of the former dissolved in two parts of 

 water. If done properly there is no danger of contaminating the 

 culture medium from the alkaline pyrogallic-acid solution. The 



