30 INFECTIOUS AND PARASITIC DISEASES. 



strongest support to the view, formerly much debated, 

 that fever is a benign and necessary feature in the class 

 of diseases we are discussing. The modern concep 

 tion of disease takes the position that recovery fror 

 an infection is always brought about either through th 

 production of an immunizing substance by the bod} 

 or through the introduction of the same from without. 

 In the body, the period of invasion marks the beginning 

 of antibody formation, which from this time goes on 

 until either recovery or death supervenes. If the former, 

 sufficient antibody is formed to equalize the bacteria 

 or their poisons and prevent further inroads of either 

 upon the tissues; if the latter, the body's defensive 

 mechanism fails to act through weakness, or is over- 

 come by the intensity and massiveness of the virus. 

 The use of antitoxin in disease marks the highest refine- 

 ment of specific medication, in that an immunizing sub- 

 stance is injected into a patient which can be depended- 

 upon to counteract or neutralize a definite poisonous- 

 (toxic) substance. It aims to take from the patient 

 the burden of producing antibodies, which at best is 

 slow and too often a doubtful quality, by injecting 

 them fully formed and active. These have been pre- 

 pared from some animal which has been subjected to 

 the poison and has recovered. In other words, the 

 immunity forced upon an animal is transferred to the 

 patient. From what has been said concerning the 

 action of antibodies in that they only neutralize their 



