AGOLUTINATION. 107 



Virulent and avirulent cultures are alike affected; even the 

 expressed bacterial cell-juice and, moreover, the germ-free 

 filtered bouillon culti^res are precipitated by specific im- 

 mune sera (Kraus, Wion. med. Pr., 1897, 608). 



The paralyzed and clumped organisms are not dead, or 

 only partially so, for after twenty-four hours an active in- 

 crease of the organisms is often observed. Although the 

 clumps do not dissolve, and at most loosen up, the prepa- 

 ration swarms with actively motile forms. If one adds 

 new bacteria to a preparation in a state of agglutination, 

 the}' are not affected, the agglutinin having been consumed, 

 and with the addition of new serum agglutination again 

 occurs. 



2. 1 Demonstration of specific bactericidal ^ bodies in immune 

 sera according to R. Pfeiffer. We will employ cholera as an 

 example. If one mixes a suspension of one loopful of 

 virulent cholera culture in 1 c.c. of bouillon with 0.01 c.c. 

 to 0.03 c.c. ^ of cholera-immune serum and injects the 

 mixture into the peritoneal cavity of a healthy guinea-pig, 

 he will observe there, besides paralysis and swelling, death, 

 granular degeneration, and, finallj', solution of the intro- 

 duced germs. In this case a virulent culture must be 

 selected, since avirulent organisms, even without the addi- 

 tion of immune serum, die and are dissolved in the 

 peritoneal cavity. This reaction is specific to a high de- 

 gree (compare below). To make the examinations, peri- 

 toneal lymph is obtained with a capillary pipet through 

 a small opening in the abdominal wall, and examined 

 microscopicall}' every ten minutes for about half an hour 

 to one hour to determine the fate of the bacteria. After 

 this time, if the reaction is positive, nothing more is to be 



^ A third "specific" serum reaction has been recommended by 

 V. Diingern (C. B. xxiv, 710). A little of the serum from animals 

 which have passed through cholera and staphylococcus infection, and 

 anthrax, exerts a marked inhibitory action upon the liquefaction of 

 gelatin hj a portion (1 c.c. ) of a liquefied gelatin culture of the same 

 variety. Normal serum restrains it le&s; the interference with the 

 ferments of other varieties is slight. 



^ C. Frankel has proposed the name ' ' lysogenio material ' ' for that 

 which acts as a bactericide. 



'If one draws 0.2 c.c. in a capillary tube and divides the filled 

 length of tube into twenty parts, then each part represents 0.01 c.c. 



