60 CLINICAL BACTERIOLOGY AND HiEMATOLOGY 



centre of the lesion ; it may be necessary to make a puncture 

 with a sterilized needle before this can be done. If the fluid does 

 not rise spontaneously into the pipette, break off the other end 

 and suck gently, watching the column of fluid so that it does not 

 get into your mouth. It is safer to use a pipette with a wide 

 mouthpiece plugged with cotton-wool (Fig. 14), or, best of all, 

 to suck up the fluid by means of an indiarubber nipple. 



Having obtained a drop or two of the fluid exudate, blow it out 

 on to the surface of a clean slide and spread it out into a film ; 

 prepare as many of these as you can. Allow them to dry, and 

 stain one with Loffler's blue and some by Gram's method. 



Examine with the oil-immersion lens. Make a careful search 

 over the films, looking for large cigarette-shaped bacilli, noting 

 whether they are or are not arranged in chains. Examine the 

 Gram specimens, and see whether the bacilli are to be seen in 

 them also. 



Interpretation of Results. 



If the case is really one of malignant pustule, the chances are 

 very greatly in favour of your finding the bacilli in large numbers, 

 and the failure to do so tells strongly against a positive diagnosis. 



Culttiral Methods. — The fluid for examination is taken in exactly 

 the same way as that described above, but the isolation of the 

 organisms will be greatly facilitated if antiseptic methods are 

 employed to prevent contamination with skin bacteria. To this 

 end the surface of the lesion should be washed gently with 

 carbolic or perchloride lotion, and then (very thoroughly) with 

 alcohol or methylated spirit to remove the antiseptic. The 

 surface is then allowed to dry. 



If the material is to be transmitted to a pathologist for examina- 

 tion (and this is the wisest course to adopt, as animal inoculations 

 are almost necessary for the absolute identification of the bacillus), 

 the fluid must be carefully sucked up into the bulb, and both ends 

 of the pipette carefully sealed. 



If the examination is to be made at home, the best way is to 

 make two inoculations in gelatin. The first should be a stab 

 culture, and may be made with the pipette direct ; or the fluid 

 may be blown out into a watch-glass or on to the surface of a 

 slide (in either case sterilized by being heated in the flame and then 

 allowed to cool), and the stab made by dipping the end of a straight 

 platinum needle into the fluid, and then driving it into the gelatin. 



