SECTION III 



COLLECTION AND EXAMINATION OF CERTAIN 

 MORBID MATERIALS 



THE COLLECTION AND EXAMINATION OF PUS 



WHEN a simple microscopical examination has to be made, the 

 collection of pus presents no difficulties, as the few bacteria 

 which may gain access from the skin or the hair will not lead 

 to error. The case is otherwise where cultural examinations 

 have to be made, or where the material has to be taken to a 

 laboratory. Here the material should be collected in a pipette. 

 The best form to use is the "opsonin" pipette (see Fig*. 35), 

 plugged with cotton-wool at the wider end. It may be steril- 

 ized by dry air, or more simply by passing it through the flame 

 several times, taking care to make each part very hot, but not 

 hot enough to soften the glass. 



When the abscess has been opened, a considerable quantity 

 of pus should be allowed to flow out, and the sterilized pipette 

 is then to be passed through the incision (care being' taken to 

 avoid contact with its sides) and the pus carefully sucked up 

 into the bulb,^ using an indiarubber nipple. The fluid thus 

 obtained may be used to inoculate cultures there and then, or 

 the end of the pipette may be sealed in the flame. 



THE EXAMINATION OF Pus. 



The organisms which may cause pus are extremely numer- 

 ous, the most important being streptococci, staphylococci, the 

 pneumococcus and the gonococcus, the bacilli of typhoid 

 fever, tuberculosis, and glanders, the B. coli communis, the 

 B. pyocyaneus (the organism which produces blue pus), and 

 the fungus of actinomycosis. In the majority of cases the 

 organism which is present in a given sample of pus can be 



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