1 66 Immunity 



hours in the refrigerator, and the amount of solution gauged by the 

 naked eye supplemented by microscopical examination of the tissue 

 elements. 



Bacteriolysins. The first observations upon bacterioly- 

 sis was made in 1874 by Traube and Gescheidel,* who found 

 that freshly drawn blood was destructive to bacteria. The 

 matter was pursued by numerous subsequent investigators 

 and was explained by Buchner as depending upon alexines. 

 Pfeifferf described the peculiar reaction known as "Pfeiffer's 

 phenomenon." Ehrlich and Morgenrothf and Bordet de- 

 scribed the mechanism of cytolysis, explaining the "Pfeiffer 

 phenomenon" and paving the way for future experiments. 



Direct destruction of bacteria by blood-serum and body 

 juices is rare, and occurs only when the serum contains 

 appropriate quantities of both factors involved i. e., ambo- 

 ceptor and complement. For the usual bacteriolytic 

 investigations it is, therefore, necessary to consider three 

 factors: i, The bacteria to be destroyed; 2, the serum fur- 

 nishing the complement; and 3, the serum furnishing the 

 immune body. 



1. The bacteria to be destroyed should be prepared in the form of a 

 homogeneous suspension similar to that employed for making the ag- 

 glutination tests. It is best to use the surface growths from agar-agar, 

 rubbed between glasses or ground with sodium chlorid solution, added 

 drop by drop, in a mortar, or well rubbed upon the side of a test-tube 

 containing the fluid, which is permitted to contact with the mass from 

 time to time by inclining the tube so that the fluid is able to carry 

 away the bacteria as they are distributed. 



If quantitative estimations are to be made, the number of bacteria 

 in the suspension must be known or at least a standard quantity must 

 be employed, as the destructive process is a chemical one, in which the 

 destructive agents are themselves used up. 



2. The serum furnishing the complement is a normal serum- that is, 

 the serum from a healthy animal that has undergone no manipulation. 



3. The serum containing the amboceptor or the immune body is 

 obtained from an animal that has been given a high degree of immuni- 

 zation against the bacterium to be destroyed or dissolved. If it is 

 desirable, any complement contained in this serum can be destroyed 

 by heating for a short time to a point just short of coagulation. 



These three having been prepared, an appropriate quantity of the 

 bacterial suspension is placed in a small test-tube, and an appropriate 

 quantity of the normal serum added. To this mixture of two constants, 

 varying quantities of the immune serum is added and the tube stood 

 away for twenty-four hours on ice. In most every case it will be found 

 that the immune serum contains a great quantity of agglutinating 



* " Jahresb. der Schles. Ges. f. vaterl. Kultur," 1874. 

 f "Deutsche med. Wochenschrift," 1896, No. 7. 

 J "Berliner klin. Wochenschrift," 1899 

 "Ann. de 1'Inst. Pasteur," xn, 1898. 



