168 BIOLOGY AND TECHNIQUE 



The intestines are pulled aside so as to uncover the kidneys. With a fresh 

 set of instruments, the hilum of the kidney is now grasped and the kidney 

 rapidly separated from its capsule and passed through the flame before 

 being placed into a sterile Petri plate. The spleen may be removed in the 

 same way. 



The kidney and spleen should then be cut up with the utmost precautions 

 of sterility. Work in a dustless place with the windows closed and several 

 Bunsen flames going close to the field of operation. An assistant slightly 

 raises the cover of the Petri plate and the bacteriologist, working with sterile 

 forceps and a sterile old knife which can be constantly flamed, cuts the 

 kidney in pieces of appropriate size against the bottom of the plate. In 

 placing these bits of tissue into tubes, the stopper of the sterilized tube 

 is pulled, and the tube heated around its' lips and upper one-half inch. 

 The tissue is then rapidly passed into the flame, thrust into the mouth of 

 the tube, the cotton stopper flamed and inserted. The tube is then given 

 a rapid flip with the hand, which sends the tissue to the bottom. When 

 these tubes are filled with broth and ascitic fluid or agar, they should be 

 incubated before use and the unsterile ones discarded. 



In most of Noguchi's work, and some of our own, paraffin oil was used 

 over the tops of these tubes. The sealing properties of this, however, are 

 not what they were formerly supposed to be. Air passes through this 

 paraffin oil, and if sealing is desired it is much better to heat the upper 

 empty part of the tubes thoroughly, and thrust in a paraffin stopper. The 

 top of the fluid also can be covered with melted paraffin which will solidify 

 in the incubator. 



Cooked Meat Medium, Robertson, 45 for the Cultivation of Anaerobes. 

 250 grams of beef heart are minced and ground in a mortar. Add 250 c.c. 

 of tap water, heat slowly, cook thoroughly, neutralize to litmus with NaOH, 

 tube and sterilize in autoclave. 



The simplest method of making cooked meat media which gives satis- 

 factory results with the majority of the anaerobic bacilli, is the following. 

 A few pieces of chopped meat (not necessarily heart) are placed in the 

 bottom of the tube, enough infusion broth, P H 7.8, is added so that there 

 are about 3 c.c. clear broth over the meat. The medium is ready for use 

 after autoclaving. The reaction usually becomes more acid on autoclaving 

 in the presence of the meat fragments. The optimum for the most anaerobic 

 bacilli is P H =7.4. 



Enriching Substances Used in Media. For the cultivation of 

 microorganisms which are sensitive to their food environment, it is 

 often necessary or advisable to add to the ordinary media enriching 

 substances, which empirical study has shown to favor the growth 



ts Robertson, Jour, of Path, and Bacter., January, 1916, 20, No. 3. 





