226 ANIMAL INOCULATION 



sterile receptacles. The site of the puncture should be 

 shaved and disinfected before the instrument is introduced. 



Discharges of whatever kind should likewise be collected 

 in sterile receptacles and examined as soon as may be. 



If internal organs are to be examined it is best to kill a 

 moribund animal than to wait for death, since after death, and 

 in severe infections, even sometimes before, the tissues are 

 rapidly invaded by saprophytic bacteria from the alimentary 

 and respiratory tracts which complicate greatly the isolation 

 of the specific organism . Hence the search for specific bacteria 

 in carcasses or organs several hours after death is frequently 

 negative. Animal inoculation with such material is very often 

 followed by sepsis or septicemia in a few hours, so that the 

 specific organism has no opportunity to manifest itself. 



In securing material for cultures from internal organs it is a 

 good plan to burn the surface of the organ with a gas or alcohol 

 flame, or to sear it with a hot instrument to kill surface organ- 

 isms, then make the incision or puncture through the burned 

 area and secure material from the interior of the organ. Such 

 punctures made with a stiff platinum needle frequently give 

 pure cultures of the organism sought. Slides may be made 

 from such material and culture media inoculated at once. 



Since a bacteriological diagnosis depends most commonly 

 on growing the organisms, it is evident that material sent 

 for examination must never be treated tvith an antiseptic or pre- 

 servative. If decomposition is to be feared the only safe pro- 

 cedure is to pack the material in ice and forward in this way. 



Tuberculous material from the parenchyma of internal 

 organs may be forwarded in a preservative (not formalin, 

 since this makes it very difficult to stain the bacteria), aswi 

 this special case a very positive diagnosis may be made by 

 staining alone. Even here it is better to pack in ice in 

 order that the diagnosis by staining may be confirmed by 

 inoculating the living organisms into guinea-pigs. 



In the case of material from a rabid animal and many 

 protozoal diseases the rule against preservatives is not abso- 

 lute, since staining is a reliable diagnostic means. Even in 

 these cases it is often desirable to inoculate animals, hence, 

 as before stated, it is best to make it a uniform practice to 

 pack material for examination in ice and use no preservatives. 



