THE COLLECTION AND EXAMINATION OF PUS 121 



The pneumococcus, gonococcus, the fungus of actinomyces, and 

 the tubercle bacillus, will not grow on these plates ; the strepto- 

 coccus and the bacillus of glanders will grow feebly, if at all. 



In a day or two longer the plates will, in some cases, be found 

 to have undergone a decided change. If liquefying organisms are 

 present the colonies will soon become depressed below the general 

 surface of the medium, and will be surrounded by haloes which 

 consist of liquefied gelatin. This will happen with the staphylo- 

 cocci and the B. pyocyaneus ; not with the streptococci, the 

 typhoid bacillus, nor with the B. coli. 



The bacillus of blue pus can readily be distinguished from the 

 staphylococci by its morphological appearance (it is a slender rod), 

 and by the fact that the gelatin round the colony is coloured blue 

 or bluish-green, the growth itself being nearly white. 



Material containing a mixture of bacteria can also be separated 

 very simply by making tube-plates on agar, selecting for the purpose 

 sloped tubes containing a good amount of water of condensation 

 in each ; old dry tubes are useless for the purpose. Place a drop 

 of pus on the surface, and with a platinum loop smear it over the 

 medium, and at the same time tilt the tube so that the water of 

 condensation mixes with the pus, and also flows over the surface. 

 Take a loopful of this water of condensation, and repeat the pro- 

 cess in a second tube, proceeding just as you did with the drop of 

 pus in the first, and in a similar way inoculate the third tube from 

 the second. Put the tubes upright, so that the excess of fluid 

 may drain off the upper part of the slope. One of the cultures 

 will (after incubation) probably show separate colonies, from 

 which pure subcultures can be made. 



Interpretation of Results. 



The chief practical value of the bacteriological examination of 

 pus is derived from the fact that if specific vaccine treatment (on 

 Wright's system) is to be used, the vaccine must be prepared from 

 the organism which is causing the disease. If a patient is suffer- 

 ing from a staphylococcic lesion, it is not much use inoculating him 

 for pneumococci, or vice versa. I have seen and obtained such 

 excellent results in some cases by treatment of this nature that 

 very little doubt remains in my mind that the method is one which 

 will be widely used in the future. Except for this the results 

 obtained by a study of the bacteria in pus are more of scientific 



