282 BACTERIOLOGY. 



drop or two of the fairly strong solution of the dye (gentian 

 violet, p. 147), is then added, and the specimen is gently 

 swayed for a few seconds (5-10). The cover-glass is then 

 washed as rapidly as possible, and, after drying the clean 

 under surface, it can be examined. Scarcely any color will 

 be seen by the eye, but under the microscope the bacterial 

 cells will be seen deeply stained, with hardly any colored 

 back-ground. Hanging-drop examinations of any exudate 

 that may be present, and of the heart-blood should be made. 



The necessary material for cultivation should be placed 

 in culture tubes, which can be then set aside until the micro- 

 scopic examination is completed and the animal disposed 

 of. Gelatin or agar plates are then made from this mater- 

 ial. The material should also be planted in bouillon and 

 should be streaked over the surface of an inclined agar 

 tube. Isolated colonies may be obtained by successively 

 streaking a number of agar tubes in the manner described 

 on p. 238. The agar and bouillon tubes should then be set 

 aside in an incubator and allowed to develop. 



In the post-mortem work proper, the greatest care is 

 taken to prevent the introduction of foreign organisms, 

 since these might give misleading results. Throughout the 

 work, however, the operator must be extremely careful to 

 prevent personal infection. The rule to sterilize every in- 

 strument shortly before and immediately after use, before 

 it has left the hands, must be strictly attended to. Direct 

 contact of the hands with infectious matter must be care- 

 fully avoided, and when such contact has taken place 

 prompt disinfection must be resorted to. It may be well in 

 this connection to call attention to the precautions empha- 

 sized on p. 170. When blood or pieces of tissue adhere to the 

 instruments, the latter should not be placed at once into the 

 flame, inasmuch as the sudden heating may cause the ma- 

 terial to spurt and scatter about. To avoid this, the ma- 



