ANTI-BODIES. 19 



body. Specific immune bodies are produced for many substances, 

 toxins, bacterial cells, red blood cells, ferments, etc. As a result 

 of this multiplicity of substances that can cause the cells to 

 produce anti- bodies, ant i- bodies may be anti- toxic, aggluti- 

 nating, precipitating, lytic, etc. To produce agglutination, 

 precipitation or lysis it is necessary that a ferment-like sub- 

 stance be a part of, or able to combine with, the immune body. 

 This ferment-like substance, as stated before, is labile and lost 

 on ageing, heating, etc. When this is lost the serum containing 

 the immune body is said to be inactive. In normal serum there 

 is present a substance called complement which can again reacti- 

 vate a lytic serum. The agglutinating power, however, cannot 

 be restored by the addition of fresh complement. Complement 

 can be preserved for long periods of time if the serum is dried 

 without heat soon after the blood is drawn. Whether there is 

 only one complement or a multiplicity of the same has not been 

 definitely decided, Ehrlich assuming that there is a multiplicity 

 of the same, while Bordet and Buchner claim there is only one. 



It has been demonstrated that anti-toxic substances are im- 

 portant in preventing the action of toxins on the body cells, while 

 lytic substances have been found to protect the body by the 

 solution and destruction of bacteria. Whether the agglutinat- 

 ing or precipitating substances are of importance in destroying 

 bacteria, is by no means certain. Numerous investigators as- 

 sume that they injure and change the bacterial cells or substances 

 used in immunization, while others claim that they exert no 

 such action. It has been quite definitely observed that it is pos- 

 sible to cultivate and grow bacteria that have undergone ag- 

 glutination. 



As has been stated earlier, immune bodies are formed only 

 for such substances as are able to combine firmly with the recep- 

 tors of the cells, and it is on this assumption, that Ehrlich explains 

 the impossibility of producing immunity to certain poisons, as 

 the alkaloids, strychnine and morphine. 



The cells whose receptors anchor the substances and cells for 

 which immune substances are formed, are probably widely dis- 

 tributed throughout the body. The particular tissues in which 

 anti-bodies are formed has not been determined and probably 

 varies for the different substances to which immunization can be 



