NON-SPECIFIC RESISTANCE. 173 



special objection to this theory that it puts im- 

 munity on a non-specific basis; i. e., pyocyanase 

 will protect against anthrax, diphtheria, etc., 

 while, in reality, all our clinical and experimental 

 data point to the high specificity of acquired 

 immunity. 



In contrast to the specific immunization which 

 may be accomplished with an immune serum, it is 

 important to recognize that a non-specific increase 

 in resistance may be caused by the injection of a 

 number of substances, which in the test-tube have 

 no destructive action on the bacteria. Issaeff 

 injected into the peritoneal cavity such substances 

 as bouillon, tuberculin and sterile urine, and found 

 the resistance of the animals increased to the peri- 

 toneal inoculation of virulent organisms. Normal 

 serum from another animal has a similar effect, 

 but, in this instance, the bactericidal substances of 

 the foreign serum may be a factor in the new 

 resistance. Supposedly, this non-specific resistance 

 is local, and it appears to depend on the attraction 

 of an increased number of phagocytes and of addi- 

 tional complement (alexin) to the peritoneal cav- 

 ity. The suggestion that, preceding laparotomy, 

 nucleinic acid be injected into the abdominal cav- 

 ity, in order to increase the local resistance, has 

 its foundation in the experimental work cited. 



The serum of an animal acquires antibodies not immune 

 only for bacteria and toxins, but also for many Cyt< 

 other cells and substances which may be injected. 

 There are many immune cytotoxins, such as the 

 hemolysins, leucotoxins, neurotoxins, nephrotoxins, 

 etc., which are formed as the result of immuniza- 

 tion with the corresponding cells. (See "C} T to- 

 toxins.") 



