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DECLINE OF DIPHTHERIA AS A CAUSE OF DEATH (1880-1942) 



The long zigzag line shows the fluctuation in deaths from diphtheria per 100,000 

 population in New York (Manhattan and Bronx, for which the most complete records 

 are available). After 1895, when antitoxin came into use, there is a rapid drop, and 

 then a steady decline for twenty-five years. With the introduction of the Schick test 

 for susceptibility and the immunization of children against diphtheria, this disease 

 became an almost negligible cause of death. The record for the last few years is 

 shown in the inset, as the figures are too small to show on the large graph 



And we can say that the Hves of milHons and millions of children have been 

 prolonged into adulthood. But these two discoveries illustrate an important 

 principle of living matter. They lead on to a better understanding of life, 

 and possibly to better ways of managing our lives. 



The important principle in immunization is represented by the familiar 

 fact that if you annoy a cat she is likely to strike back. We might generalize 

 the idea further: Living matter tends to react to changes in a way that 

 neutralizes or counteracts disturbances in metabolism. Chemical disturb- 

 ances call out chemical responses. A specific poison calls out a specific 

 counter-poison — something that is chemically related to ]ust that, and not to 

 disturbances in general, not to poisons in general. 



Chemical Conflict We may think of the formation of an antitoxin as 

 a normal result of the interaction between two kinds of protoplasm. It 

 should not seem strange that among the hundreds of species of micro- 



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