METHODS USED IN CULTIVATION OF BACTERIA 



157 



are imperfectly observed. This was noticed first by Theobald Smith and 

 by Tarozzi and has become an extremely useful reenforcement to other 

 methods. It has been utilized most extensively by Noguchi of recent 



Fig. 41. — Incubator. 



years in his technique for the cultivation of various treponemata. 

 The simplest way to apply this method is to place a piece of freshly 

 excised rabbit kidney, testicle, or spleen into the bottom of a high test 

 tube (20 cm.) and then pouring over it the culture fluid- Kidney or 



