PFEIFFER'S REACTION 177 



is necessary, while after lysis has taken place the latter 

 loses the power of dissolving bacteria. The same holds 

 good for haemolysis, and the facts relating to bacteriolysis 

 and haemolysis are almost interchangeable. 



Anti-endotoxic sera. The comparative inefficiency of anti- 

 microbic sera, particularly typhoid, led Macfadyen to attempt to 

 prepare sera with microbial endotoxins, and the work has been 

 continued by Siidmersen and the writer. The method was to 

 immunise horses with the endotoxin obtained by the method 

 described on p. 40. With a typhoid serum so prepared Goodall 

 and the writer obtained promising results. 1 



Method of applying Pfeiffer's reaction. For Pfeiffer's test, the 

 organism must be virulent, and a high-grade immune serum is 

 necessary. If the organism is not virulent, it is spontaneously 

 destroyed in the peritoneal cavity without the addition of immune 

 serum. The method may be best explained in the case of a vibrio 

 supposed to be the cholera vibrio. The cholera-immune serum 

 (obtained from a horse repeatedly injected with cholera culture) 

 should possess a titre of not less than 0-0002 c.c., i.e. this amount 

 of serum mixed with one loop (2 mgrm.) of an eighteen-hour agar 

 cholera culture (virulent), suspended in 1 c.c of broth, and injected 

 into the peritoneal cavity of a small guinea-pig should cause granular 

 degeneration and bacteriolysis of the vibrios within one hour. 



Four mixtures are made (a) one loop of an eighteen-hour agar 

 culture of the vibrio to be tested, 0-001 c.c. cholera-immune serum, 

 suspended in 1 c.c. of broth ; (&) the same as (a), but 0-002 c.c. 

 cholera serum ; (c) the same as (a), but 0-001 normal serum of an 

 animal of the same species as that furnishing the cholera serum ; 

 (d) one quarter loop of the vibrio in 1 c.c. of broth, as a control of 

 the virulence of the culture. These mixtures are then injected into 

 the peritoneal cavities of four guinea-pigs each of about 250 grin, 

 weight. At intervals of thirty and sixty minutes hanging-drop 

 preparations are made of the peritoneal fluid of each animal, the 

 fluid being obtained by inserting a capillary pipette through a 

 minute incision in the skin. In the guinea-pigs injected with (a) 

 and (6), if the organism be cholera, the vibrios should show marked 

 degenerative changes within sixty minutes, while (c) and (d) will 

 show plenty of active vibrios. If the organism be non-virulent, 

 two methods may be adopted for applying the Pfeiffer reaction. 

 The first, a microscopical or direct method, is carried out by micro- 



1 Proc. Roy. Soc. Med., vol. ii, 1907-8, Med, Sect., p. 245 et seq. 



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