BACTERIOLOGICAL EXAMINATION OF MATERIAL 207 



cardium, or the peritoneum may be taken with a sterilized syringe 

 or pipette. Under all circumstances it should be remembered that 

 cultures taken from blood or tissues of the cadaver will be con- 

 taminated, unless cultures are taken within a few hours after death. 

 Bacteria get into the circulation and multiply throughout the body 

 with astonishing speed after death. 



Materials collected at the bedside or in the operating-room should 

 be transferred directly to the proper media or else into sterile test 

 tubes and so sent to the laboratory. When the material is scanty, 

 it may be collected upon a sterile cotton swab, which should be 

 immediately replaced in the sterilized containing tube and sent to 

 the laboratory. 



Syringes, when used for the collection of exudates or blood, 

 should be of some variety which is easily sterilizable by dry heat, 

 or boiling. Most convenient of the forms in common use are the 

 all-glass "Luer" syringe, or the cheaper "Sub-Q" model. Instru- 

 ments which can be sterilized only by chemical disinfectants should 

 not be used. When fluids are collected for bacteriological examina- 

 tion, such as spinal fluid, ascitic fluid, or pleural exudates, it is 

 convenient to have them taken directly into sterilized centrifuge 

 tubes, since it is often necessary to concentrate cellular elements by 

 centrifugalization. By immediate collection in these tubes, the 

 danger of contamination is avoided. 



Examination of Exudates. Pus. Pus should first be examined 

 morphologically by some simple stain, such as gentian-violet, and 

 by the Gram stain. It is convenient, also, to stain a specimen by 

 Jenner's stain, in order to show clearly the relation of bacteria to 

 the cells. Such morphological examination not only furnishes a 

 guide to future manipulation, but supplies a control for the results 

 obtained by cultural methods. Specimens of the pus are then trans- 

 ferred to the proper media, and pour-plates made or streaks made 

 upon the surface of previously prepared agar or serum-agar plates. 



A guide to the choice of media is often found in the result of 

 the morphological examination. In most cases, it is well also to 

 make anaerobic cultures by some simple method. (See page 179 

 et seq.) 



The colonies which develop upon the plates should be studied 

 under the microscope, and specimens from the colonies transferred 

 to covor-glasses and slides for morphological examination and to the 

 various media for further growth and identification. Animal inocu- 

 lation and agglutination tests must often also be resorted to. A 



