CHAPTER X 



THE BACTEEIOLOGICAL EXAMINATION OF MATEEIAL FEOM PA- 

 TIENTS AND AN OUTLINE OF THE BACTERIAL FLORA OF 

 THE NORMAL HUMAN BODY 



TECHNICAL procedures for the examination of specimens of 

 exudates, stools, sputum, etc., in various conditions are given in 

 appropriate places in the text dealing with the individual diseases. 

 In this chapter we wish to discuss briefly general principles of 

 bacteriological examination which will be useful in properly col- 

 lecting and handling materials which are sent to the laboratory 

 for diagnosis or which the bacteriologist takes from the patient 

 himself. 



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 trans- 

 ferred 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 capsule 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 autopsy 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 peri- 



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