360 ANTHRAX 



wavy margins by means of a hand lens. They should also be 

 examined microscopically by means of film preparations. 



While the isolation of the b. anthracis from fresh material is 

 usually easy, great difficulty may be encountered where the 

 organism is to be sought for, in, say, a carcase which has been 

 dead for from twenty-four to forty-eight hours, as the bacilli 

 rapidly die out or are associated with putrefactive organisms. 

 In such cases methods have. been applied with a view to put- 

 ting the organisms in specially favourable circumstances for 

 growth and especially for sporulation ; in one of these the 

 so-called Strassburg method the suspected blood or tissue 

 juice is spread on moist sterilised sticks of plaster and incubated 

 in a moist chamber, and Miiller and Engler have modified 

 this by substituting for the plaster sterilised pieces of flower-pot 

 placed under similar conditions. 



(c) Test Inoculation. A little of the suspected material 

 should be mixed with some sterile bouillon or water, and 

 injected subcutaneously into a guinea-pig or mouse. If anthrax 

 bacilli are present, the animal usually dies within two days, with 

 the changes in internal organs already described. The diagnosis 

 of an organism as the anthrax bacillus cannot be said to be 

 substantiated till its pathogenicity has been proved. 



(d) Ascoli's Thermo-precipitin Reaction. This depends on the 

 observation that certain anthrax immune sera produce a pre- 

 cipitin reaction with the products of the b. anthracis. The 

 suspected blood or tissue is boiled for a few minutes in five to 

 ten volumes of normal saline containing one part per thousand 

 of acetic acid ; the fluid is cooled and filtered through paper or 

 asbestos so as to obtain a clear filtrate ; a little of this is then 

 run on to the top of the serum, and a white ring should form 

 immediately at the junction of the fluids. The reaction some- 

 times occurs with normal sera, but in this case does not appear 

 for a quarter of an hour. It is absolutely necessary that the 

 serum to be used should be previously tested with material derived 

 from an undoubted anthrax case, as only a certain small proportion 

 of immune sera will give the reaction. The reaction seems to 

 depend on an effect produced between the serum and substances 

 derived from the bacilli, as it is most marked with tissues con- 

 taining numerous organisms. It can be obtained with material 

 which has been kept for six months, and numerous controls 

 made with tissues of animals dying from other diseases are stated 

 to have given negative results. 



