X"VI. TYPICAL METHOD OP STAINING ANTHRAX 

 BACILLI PROM THE BLOOD IN COVER-GLASS 

 PREPARATIONS. 



According to Johne the anthrax bacillus in the blood has a typi- 

 cal structure which no other bacillus presents under similar condi- 

 tions. By this peculiar structure the anthrax bacillus can quickly 

 and absolutely be diagnosed from other large cadaver bacilli often 

 found in the blood of animals from ten to fifteen hours after death 

 and with which bacilli the anthrax bacillus is often confounded. 



It is well known that the many organisms are surrounded by 

 a colorless, gelatinous sheath or membrane (often overlooked even 

 when present; similar to the membrane, for instance, frequently 

 seen in some of the higher plants, such as the unicellular algae. Dif- 

 ferent environments alter the appearance of this membrane, it 

 some times being very evident and at others scarcely visible or absent 

 in the same organishi. For instance, there are several T)athogenic 

 bacteria, such as the micrococcus tetragenus, micrococcus as- 

 coformans, and Friedlander's capsule-coccus of pneumonia, 

 which within the body shows a well-defiued membrane or capsule, 

 while if grown upon an artificial media this capsule is lost. The 

 same is true of the anthrax bacillus, 



If a coTer-glass preparation is made from the blood 

 or from the organs of an anthrax animal and is intensely 

 stained with gentian-violet or with fuchsin, there will 

 generally be noticed enormous bacilli of different lengths; 

 with irregular outlines and often with prolonged, rounded 

 swellings at the ends. In such cases it is only with 

 difficulty that the separate cells can be dis- 

 tinguished. If now this preparation is decol- 

 orized in 1 to 2 per cent, acetic acid and again be 

 examined a marked alteration will be observed. The 

 bacilli are now seen occuring singly, in pairs, or in distinct 

 chains of varying lengths, still well stained but much 

 smaller than before; their outlines are perfectly regular, 

 except where one is undergoing the process of division, 

 and the ends of the rods are square or more often slightly 

 convex => <= never concave =3 1= Surrounding the 

 bacilli, however, is observed a perfectly distinct, colorless 

 membrane. This membrane is apt to be irregular in out- 

 line, and its ends are often swoUen; it is now very evi- 

 dent that it was this membrane (stained in the first prep- 

 aration) which caused the apparent size and irregular 

 shapes of the organisms. 



It has been suggested that this capsule-like mem- 

 brane is nothing more than serum clinging to the organ- 

 isms. This theory cannot, however, be accepted, for not 

 only would such serum be washed away from the bacilli 

 if dUuted many times with water (which is not the case), 



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