22 AIDS TO BACTERIOLOGY 



Conversely, if no syphilitic antibody exists in the patient's 

 blood, the complement is left free, and is deviated to the 

 sensitiser of the haemolytic serum, and allows this to cause 

 haemolysis of the blood-corpuscles. 



Controls with normal and with syphilitic sera with and 

 without antigen are put through at the same time. Cul- 

 tures of the treponemes do not prove suitable antigens, 

 but various other substances act as well as the liver of a 

 syphilitic foetus e.g., alcoholic extract of normal heart- 

 muscle + cholesterin. For this reason the reaction is 

 not a true antigen test. (See also p. 182.) 



Bacteriolysis and Antimicrobic Sera. If an animal 

 be treated with gradually increasing doses of an organism, 

 an immunity against this organism is, to a certain extent, 

 created. If a mixture of the animal's serum with the 

 bacteria be injected into an animal, subsequent examina- 

 tion shows the bacteria in a state of dissolution (bacteri- 

 olysis orPfeiffer's phenomenon). InPfeiffer^s reaction this 

 solution of bacteria is applied to determine the species of 

 an organism, particularly of the cholera vibrio. Two 

 milligrammes (a loopful) of an eighteen or twenty-four 

 hour agar culture of the virulent isolated vibrio is sus- 

 pended in 1 c.c. of broth containing 0-001 c.c. of the serum 

 of an animal very efficiently immunised to cholera. The 

 mixture is injected into the peritoneal cavity of a 250 

 gramme guinea-pig. After intervals of thirty and sixty 

 minutes, some of the peritoneal fluid is abstracted by a 

 sterile capillary pipette, and a hanging -drop preparation 

 made therefrom. If the organism be V. cholerce, the 

 bacteria are seen broken down into granules. A control 

 experiment with normal serum is made. 



The bodies bringing about this phenomenon are known 

 as bacteriolysins. Bacteriolysis is brought about by two 

 substances, an immune body different for each organism, 

 and only existing subsequent to treatment with the 

 specific organism, and an addiment, complement, or alexin, 

 present in normal serum. The complement is highly 

 unstable, and present in small amount, thus restricting 

 the curative power of antityphoid and anticholera sera. 



Deviation of the Complement. An excess of immune 

 body in a serum proves as inefficient for bacteriolysis as 

 too small a quantity. Some amboceptors unite with the 

 receptors of the bacterial cells, while others combine with 



