DIAGNOSIS OF ANTHRAX 345 



a prompt reply. In many cases the health of other animals is 

 at stake and sometimes it is the health of some of the people 

 who have had to do with the care of the animal while sick or 

 after its death. The element of time required in making a 

 diagnosis is therefore of considerable importance. 



LABORATORY PROCEDURE 



A smear is first made from the sample of blood, spleen, pulp 

 or blood from a subcutaneous ear vein as the case may be. This 

 is stained with any of the common stains and examined im- 

 mediately. In case the material is fresh and the case is positive 

 the anthrax organisms will be found in abundance. Tn these 

 cases the McFadyean reaction works beautifully. If the material 

 has putrefied to any extent, organisms which closely resemble 

 the anthrax bacterium are usually present. There may be 

 several kinds of these organisms in a single sample. In addition 

 to these there are nearly always present some larger organisms 

 of a rod shape and having a slight resemblance to B. anthracis, 

 and various organisms of other kinds. I have not had success 

 with the McFadyean reaction in picking out anthrax organisms 

 from such a mixture and the morphology can be taken as of 

 no greater significance than as a suggestion of anthrax. 



Cultures are made on plain agar plates. A small bit of tissue 

 or a drop of blood is placed in a tube of bouillon and shaken. 

 From this dilution, a loopful is smeared over the surface of one 

 or more agar plates, using a bent glass rod as a spreader. If 

 the material is relatively fresh and the number of bacteria does 

 not appear to be great, the dilution is done away with, the plates 

 being smeared directly. The cultures are incubated at 37°C. 

 and -examined after eighteen to twenty-four hours. 



Many of the large organisms having some resemblance to B. 

 anthracis, found in putrefying blood and tissue are anaerobes 

 so that samples showing large numbers of these will usually show 

 only a few Bad. coli or miscellaneous organisms on the plates. 

 In these cases, a diagnosis of "Unable to find anthrax" is made. 

 Injection of guinea-pigs does not yield any result as far as a diag- 



