IMMUNITY AND SPECIFIC 

 THERAPY 



CHAPTER I 

 INTRODUCTORY AND GENERAL 



IMMUNITY is the power which certain living organisms possess of 

 resisting influences which are deleterious to others. In its widest 

 form it includes the power of resisting poisons, adverse physical 

 influences, and diseases of all kinds. Thus, many men can and 

 do acquire some degree of immunity against nicotine, alcohol, and 

 other poisons ; some bacteria are immune to temperatures which 

 are quickly fatal to others ; and some individuals and races have 

 a very real immunity to gout and other metabolic diseases to 

 which their less fortunate brethren are more prone. In any 

 complete discussion of the subject these forms of immunity would 

 require some consideration, but in what follows we shall, in the 

 main, limit ourselves to the investigation of immunity against 

 the diseases of bacterial origin. In doing so we must not be 

 thought to consider the other diseases metabolic and what not 

 as being unimportant. The very reverse is the case, and the 

 subject which calls most urgently for research at the present day 

 is the nature and mechanism of immunity against malignant 

 tumours, and of this we have recently acquired a little know- 

 ledge. But the diseases other than those of bacterial origin will 

 not be dealt with, for the simple reason that our knowledge of 

 their intimate causes is still unknown, and until they are dis- 

 covered, and until the physiological disturbances of the economy 

 which occur in these diseases are more fully known, the nature 

 of the corresponding immunity is obviously extremely difficult 

 of study. The bacterial diseases are quite different, for here 



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