CHAPTER XXXI 

 EXAMINATION OF PUS 



Pus may be collected for examination either i. with a platinum loop, 

 2. with a sterile swab, 3. with a bacteriological pipette or 4. with a 

 hypodermic syringe. 



It is always well to make a smear and stain it by Gram's method at 

 the same time that cultures are made. The Gram stain gives informa- 

 tion as to the abundance of organisms in the pus and as to the probable 

 findings in the culture. Pneumococci and streptococci are differenti- 

 ated from the staphylococci in this way without the necessity of more or 

 less extended cultural methods. 



Smears from material examined for gonococci may show Gram-negative diplo- 

 cocci which, however, do not generally have the morphology of the Gonococcus. 

 They are furthermore extracellular. 



The M. catarrhalis has been reported from urethral smears though very rarely. 

 Diphtheroid organisms are not uncommon. Gram-positive cocci are rather common 

 in smears from discharges of chronic gonorrhoea. 



When autogenous vaccines are to be made, the isolation of the exciting organism 

 is necessary. This is best done by streaking the pus, taken up with a sterile swab 

 and emulsified in a tube of bouillon, over the surface of an agar plate. Practically 

 as convenient and providing a more nutritious medium is to smear the material on 

 a loop or swab over the surface of a blood-serum slant, then to inoculate a second 

 tube from the first without recharging the loop or swab, and so on until three or four 

 tubes are inoculated. Isolated colonies should be obtained in a third or fourth tube. 



In examining blood-serum slants inoculated with purulent material, always 

 examine the water of condensation for streptococci. 



A bacteriological pipette is very useful when pus is to be sent to a laboratory; 

 the tip can be sealed in a flame and the cotton plug at the other end insures the 

 noncontamination of the contents. The material may be drawn up either with the 

 mouth or with a rubber bulb. 



The hypodermic syringe is very useful in puncturing buboes, etc., 

 especially in plague. A small pledget of cotton on a toothpick dipped 

 into pure carbolic acid and touched to a spot over the bubo, which after 

 about thirty seconds is soaked with alcohol, makes a sterile anaesthetic 

 spot at which to introduce the needle of the syringe. It must be remem- 

 bered that when plague buboes begin to soften, the plague bacilli may 



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