CHAPTER X 



THE BACTERIOLOGICAL EXAMINATION OF MATERIAL FROM 



PATIENTS 



IN making bacteriological examinations of material taken from 

 living patients, or at autopsy, the validity of result is as fully dependent 

 upon the technique by which the material is collected, as upon proper 

 manipulation in the later stages of examination. 



Material taken at autopsy should be, if possible, directly transferred 

 from the cadaver to the proper culture media. If cultures are to be taken 

 from the liver, spleen, or other organs, the surface of the organ should 

 first be seared with a hot scalpel and an incision made through the cap- 

 sule of the organ in the seared area, with the same instrument. The 

 platinum needle can then be plunged through this incision and material 

 for cultivation be taken with little chance of surface contamination. 

 When blood is to be transferred from the heart, the heart muscle may be 

 incised with a hot knife, or else the needle of a hypodermic syringe may 

 be plunged through the previously seared heart muscle and the blood 

 aspirated. The same end can be accomplished by means of a pointed, 

 freshly prepared Pasteur pipette. In taking specimens of blood at au- 

 topsy it is safer to take them from the arm or leg, by allowing the blood 

 to flow into a broad, deep cut made through the sterilized skin, than from - 

 the heart, since it has been found that post-mortem contamination of 

 the heart's blood takes place rapidly, probably through the large veins 

 from the lungs. Exudates from the pleural cavities, the pericardium, 

 or the peritoneum may be taken with a sterilized syringe or pipette. 



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 re- 

 placed in the sterilized containing tube and sent to the laboratory. 



Syringes, when used for the collection of cxudates 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. Instruments which can be 

 sterilized only by chemical disinfectants should not be used. When 



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