•912.] VAUGHAN— THE PROTEIN POISON. 211 



tion of a foreign protein into the body, the sensitization of the body- 

 cells to that protein, and finally the cleavage of that protein by the 

 ferment elaborated by the sensitized body cells. Now in nature 

 practically all the proteins that find their way into the body undi- 

 gested are living proteins, in the form of bacteria or protozoa. They 

 grow and multiply in the body, without materially disturbing for the 

 time being, the life of the individual. This continues during the 

 period of incubation but when the body cells have become sensitized 

 and begin to split up the foreign protein the period of incubation 

 ceases and that of disease begins. 



We have shown that repeated injections of foreign protein not 

 only cause fevers of various kinds, but lead to emaciation of the 

 animal body, to increased elimination of nitrogen, and to decreased 

 urinary secretion, and, in short, to all the phenomena that are char- 

 acteristic of the febrile diseases. Death from any of the infectious 

 diseases is due to one and the same poison, and that poison is a con- 

 stituent of the protein molecule. Symptoms vary in different dis- 

 eases for two reasons : In the first place, the foreign proteins have 

 different predilection places in the body in which they are deposited. 

 In the second place the ferment which splits up these foreign pro- 

 teins is specific for different diseases. The most successful diagnos- 

 tician cannot determine the nature of the bacterial organism which 

 causes the symptoms of meningitis. The symptoms are the same 

 so long as the organ involved is the same. The meningitis may be 

 due to the meningococcus, to the streptococcus, to the typhoid bacil- 

 lus, or to the tubercle bacillus. Still, the symptoms are the same 

 because the cleavage of the foreign molecule occurs in the same part 

 of the body. Again, every medical man knows how difficult it is 

 to distinguish between typhoid fever and acute general miliary tuber- 

 culosis, because in both instances the foreign protein is largely in the 

 blood current. As I have stated, most bacterial proteins have pre- 

 dilection places in which they are deposited. The typhoid bacillus 

 prefers the mesenteric and other glands ; the pneumococcus is de- 

 posited generally in the lungs, though it may be found in the intes- 

 tinal walls. The meningococcus finds its favorite place for growth 

 and development in the coverings of the brain. The tubercle bacil- 



