106 SPECIFIC INFECTIOUS DISEASES 



that has been dead but a short time. If the blood is fairly fresh, 

 the capsules of the anthrax bacteria will show well, while if the 

 bacteria show disintegration, violet masses, first described by 

 M'Fadyean, will be found lying near the anthrax germs. M'Fad- 







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Fia. 11. Blood of case of anthrax, cow, two hours before death, x 650. 



yean's method is an excellent one and has the sometimes im- 

 portant advantage of using a thick smear. A thick smear of the 

 suspected blood is made on a slide or cover glass. A slide is pref- 

 erable as it is more convenient not to mount the stained specimens. 

 The smear should be dried in the air quickly, or over a small 

 flame, then should be incompletely fixed by heat. The heating- 

 should be sufficient to fix the film to the glass; but should not be 

 enough to prevent the Hb in the red corpuscles becoming dissolved 

 during the subsequent staining and washing. Fixation is secured 

 by passing the slide, smear side up, through the flame of a Bunsen 

 burner or alcohol lamp for a second and repeating three times. 

 The under surface of the slide is just too hot for the hand to bear. 



