498 BACTERINS, SERUMS — VACCINES — ANTITOXINS 



treatment of purpura hemorrhagica. This serum originated with 

 Jensen at Copenhagen. 



Black Leg Serum. A serum for Black Leg or Symptomatic 

 Anthrax is used in certain parts of the country. It is made by im- 

 munizing a horse to gradually increasing doses of B. chauveui. This 

 serum is sometimes used in connection with the vaccine in a manner 

 similar to that described under anthrax. It really constitutes a 

 simultaneous treatment. It is also used alone for therapeutic pur- 

 poses. 



SERO BACTEEINS 



These products originated with Besredka, who in 1902, working 

 at the Pasteur Institute, Paris, brought forward what he termed 

 " Virus-vaccine sensibilis." This was prepared by mixing immune 

 serum and bacteria, permitting the mixture to stand for a while and 

 then centrifuging the bacteria out of the serum and washing them 

 entirely free by repeated centrifugalization with saline solution. 

 The bacteria attract to themselves the specific antibodies which the 

 immune serum contains, and are thus " prepared for digestion by the 

 complement as well as for immediate phagocytosis." 



In preparing these agents, the growth from an agar culture of the 

 organism is washed off with saline solutions and the suspension kept 

 at 60° C. for one hour, in order to kill the organisms. This is filtered 

 through fine silk into sterile centrifuge tubes and the corresponding 

 immune goat serum is added. The mixture is left at laboratory tem- 

 perature for 24 hours. More saline is now added and the mixture 

 eentrifuged. The supernatant fluid is poured off and the process re- 

 peated until the bacteria are washed free of serum. They are then 

 counted by Wright's method and standard suspensions made up. It 

 is claimed that these agents have a very rapid action, producing a 

 high grade of active immunity within 24 hours after the first injec- 

 tion, with simultaneous marked improvement in the condition of the 

 patient. 



Use. As yet they are not very widely used in veterinary prac- 

 tice, but the strepto- and staphylo-sero-bacterins are occasionally em- 

 ployed, also a sero-bacterin for dog distemper. 



PHYLACOGENS 



These agents are comparatively new and are based on the work 

 and experience of Dr. A. F. Schafer of California. It is his belief : 

 "'That all infections are mixed infections," that except in rare in- 

 stances, there is no such thing as an infection by a single species of 

 microorganism, that while one species may predominate the patho- 

 logic process engendered by it is accelerated and . intensified by the 

 presence of organisms of other species; in other words, that in the 

 course of an infectious disease, the symptoms are, due n.qt only to the 



