TYPHOID FEVER 65 



The explanation of these facts appears very simple. The 

 continued development of the disease after the end of the 

 incubation period or the abortment necessarily depends upon 

 the degree of acquired immunity or on the quantity of formed 

 antibody and on the quantity of bacteria which exist at this 

 moment in the organism because immunity is only relative 

 and the protection is only against a certain minimum dose 

 of bacteria. Thus the relation between these two quantities 

 which tip the balance to one side or the other, individual 

 differences between the degrees of natural or acquired immun- 

 ity at the moment of infection and finally differences of 

 quantity or virulence of the infecting bacteria may be very 

 variable. 



In the explanation of the results of these reactions it is 

 necessary to note: on the one hand, the fact, proved by 

 experiment, that the quantity of antibody formed at a given 

 moment as well as the rapidity with which it is formed is, 

 within certain limits, inversely proportional to the quantity 

 or the virulence of the injecting antigen; and, on the other 

 hand that the final result of all these reactions may depend 

 not only upon the direct action of the antigen upon the anti- 

 body or the cell which contains it but on the disturbance 

 which the lesion or the "complication" once produced will 

 cause in the function of the organism. If this is true, how 

 can we represent the causes and the origin of each pathologic 

 manifestation which characterizes the septicemic infectious 

 diseases, typhoid fever in particular? 



We know that, for the diseases caused by toxins (diph- 

 theria), cure begins with the appearance of antibodies in 

 excess while in the case of typhoid it is the disease which 

 begins precisely at this moment. We then affirm that the 

 incubation period of typhoid coincides with the disease period 

 of diphtheria or, to be more exact, that in diphtheria there is 

 simultaneously incubation, from the point of view of produc- 

 tion of antibodies, and disease with its pathologic manifes- 

 tations. And if this is true, we may assume by correlating 

 what precedes that in diphtheria pathologic manifestations 

 result from the direct action of the antigen-toxin on the 

 normal intracellular antibody and that the compounds of 

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