240 A MANUAL OF BACTERIOLOGY 



gonococcus will be especially looked for, in an empyema following 

 pneumonia the Diplococcus pneumonia, and in a tropical abscess 

 of the liver the Amoeba coli. In all cases the pus or discharge should 

 be collected with aseptic precautions in sterile capillary pipettes 

 or in sterile test-tubes at the time of operation. The discharge from 

 opened abscesses and from wounds is liable to become contaminated 

 and the original infection to be masked. In septic wounds the 

 infection may be a mixed one. 



In all cases the examination should be commenced as early as 

 possible. 



(1) Make several smears from the pus or discharge. 



(2) Stain one or two of these with L6 filer's blue and one or two 

 by Gram's method. Mount and examine microscopically. 



(a) If staphylococci only are detected, the presence of the 

 ordinary pyogenic cocci may be suspected. Proceed as in 3, 4, and 5. 



(b) If encapsuled diplococci are detected, suspect the presence of 

 the Diplococcus pneumonice, and proceed as in 3, 5, and 7. 



(c) If diplococci and tetracocci are present, note whether they 

 are in groups within the pus-cells ; if so, suspect the presence of 

 either the gonococcus or Diplococcus intracellularis meningitidis, 

 and proceed as in 6. 



(d) If free tetracocci are detected, suspect the presence of the 

 Micrococcus tetragenus, and proceed as in 3 and 4 (rare). 



(e) If streptococci are present the Streptococcus pyogenes is 

 probably the species. Proceed as in 3, 4, and 5. 



(/) If bacilli are present they may be the colon bacillus, the 

 Bacillus Welchii (aerogenes capsulatus), the bacillus of malignant 

 oedema, the tetanus bacillus, the typhoid bacillus, the Bacillus 

 pyocyaneus, or putrefactive bacilli of the Proteus group (which see). 

 The result of Gram-staining and the clinical history of the case will 

 be some guide. 



a. The colon bacillus, especially frequent in suppurative peri- 

 tonitis and in diseases of the urinary organs. (See p. 387). 



/3. The Bacillus Welchii (aerogenes capsulatus}, especially met with 

 in foul wounds and gangrenous conditions, with much development 

 of gas. (See Chapter XIII.) 



y. The bacillus of malignant oedema occurs in septic wounds 

 with septicsemic complications. (See Chapter XIII.) 



c). The tetanus bacillus is found in the wound in cases of traumatic 

 tetanus. (See Chapter XIII.) 



f. The typhoid bacillus is rare ; it may occur in suppurative 

 conditions complicating or following typhoid fever. Proceed as in 

 3 and 4. (See also p. 355.) 



