CHAPTER XVI. 



PASSIVE IMMUNIZATION (SERUM THERAPY). BACTERIOLYTIC SERA. SERUM 

 SICKNESS. ANAPHYLAXIS. SPECIAL SERUM THERAPY. 



In the former chapters it was learned that during active immunization 

 specific protective bodies were formed which circulate in the blood and can, 

 by means of the serum be transferred to another organism. By animal 

 experimentation it was further found that such bodies exert this protection 

 against fatal intoxication or infection in various ways; thus, as antitoxins 

 and antiaggressins they neutralize toxic poisons and aggressins; as bacterio- 

 lysins they bring about lysis of the bacteria; while as bacteriotropins they 

 prepare the bacteria for phagocytosis. The defending qualities of such a 

 transferred serum is evident not only if the infection is incited at the same 

 time as, or a short period after the serum is given, but in numerous instances 

 curative effects are observed if the serum is given even after infection has 

 already taken place. 



Of all sera, those with antitoxic properties have met the greatest suc- 

 cess in therapeutic application. They have already been referred to in 

 their respective chapters. 



The efficiency of the pure bacteriolytic sera on the other hand has been disap- 

 pointing. The reasons given for this lack of curative action is, in the first 

 place, the inability of bacteriolytic serum to neutralize the endotoxins. 



Pfeiffer's experiment revealed that if the number of bacteria exceeded a certain 

 limit, then in spite of bacteriolysis, death of the animal takes place. This was explained 

 by the existence of endotoxins. By bacteriolysis the endotoxins previously found 

 within the bacteria are liberated and thus get a chance to become toxic. 



The aim therefore, was to produce antiendotoxic sera. This was, however, precluded 

 from materializing by the erroneous view of Wolff- Eisner who claimed that it was impos- 

 sible to immunize against endotoxin. 



Numerous methods have been advocated for the liberation of these endotoxins: 

 maceration of bacteria, exposure to very low temperature, admixture with chemical sub- 

 stances which would dissolve the outer capsule, ferment digestion, growth upon certain 

 culture media, etc. At the present day, there is absolutely no doubt that the bacterial 

 bodies contain poisonous substances against which it is difficult and to a certain degree 

 impossible to attain an immunity. 



Whether one should adhere to the old idea and apply to these the term, endotoxin, 

 or include therein the class of true toxins with the only difference that they are not secreted 

 but contained within the bacterial body and therefore more difficult to isolate, is purely a 

 question of theoretical importance. 



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