222 APPLIED IMMUNOLOGY 



ing the bacteria to a process of autolysis, on the as- 

 sumption that the autolysis contains toxic or anti- 

 opsonic substances, and that the antigenic part of the 

 bacterin depends upon the bacteria themselves minus 

 their extractives. This disintegration of the bacteria 

 is accomplished by treating them with salt solution, 

 alcohol, ether, chloroform, or xylol, followed by filtra- 

 tion and suspension of the residue in normal saline. 



Serohacterins. — Recently, advantage has been 

 taken of Besredka s assertion, founded upon the dem- 

 onstration of Ehrlich and Morgenroth, that inocula- 

 tions with sensitized bacteria supersede in eiFective- 

 ness, rapidity of action and harmlessness ordinary 

 bacterins or bacterial vaccines. Such sensitized bac- 

 terins or "serohacterins" are prepared by treating bac- 

 teria with their specific immune serum, by which 

 process the bacteria become inseparably joined with 

 their antibodies, thereby in a state, immediately on in- 

 jection, prepared to be acted upon by the complement 

 of the patient's blood. Thus the usual delay of a week 

 or more, required for the patient to form his own anti- 

 bodies — incidentally also the negative phase and local 

 injectional reaction — using the ordinary bacterins, is 

 avoided, and immunity is secured rapidly and inten- 

 sively in twenty-four to forty-eight hours. Finally, 

 by virtue of the absence of " negative phases," the in- 

 oculations may be repeated every day or two, thereby 



