350 INFECTION AND RESISTANCE 



influence the course of such infections in animals that the results 

 of vaccine treatment in them are difficult to judge. 



In acute diseases which run a definite course, typhoid fever, 

 pneumonia, dysentery, cholera, plague, and a number of other con- 

 ditions, vaccine treatment during the course of the disease has not 

 much theoretical justification. In typhoid fever, especially, specific 

 antibodies appear in the blood in amounts enormously increased 

 above the normal at periods when the patient is still actively ill in 

 spite of the fact that the blood stream has been freed of the micro- 

 organisms. Whatever may be our opinion as to the continuance of 

 the disease after bacteria have been driven out of the blood stream, 

 the use of vaccines can only tend to further increase of antibodies 

 which are already present in amounts far exceeding normal. In 

 pneumonia the microorganisms seem curiously resistant against the 

 attack of the serum antibodies, and in spite of the presence of large 

 amounts of antigen both in the lungs and, for a time, in the circula- 

 tion the development of immunity is delayed until just before or near 

 the crisis. Since this, however, is usually only a matter of 7 or 8 

 days, it is hardly likely that the injection of vaccines during this 

 period could markedly alter the ultimate outcome. In a later sec- 

 tion we shall see that vaccine treatment in typhoid fever is neverthe- 

 less being extensively tried and gives reactions of a nature which 

 cannot entirely be explained on the basis of the above considerations. 



As we have said before, the opinions expressed above are given 

 with the purpose of stating as clearly as we can the logic of vaccine 32 

 therapy as we see it at present. The next ten years of clinical ex- 

 perience may largely modify these views. One thing is certain, how- 

 ever, and that is that the problem can only be settled if treatment by 

 this method is undertaken with the guidance of an accurate bacteri- 

 ological diagnosis, and with bacteriological control of the individual 

 case, so that, when occasion arises, estimations of antibodies can be 

 made. 



To protest against the random use of commercial stock vaccines 

 without laboratory diagnosis and without control is almost a plati- 

 tude. 



In the case of tuberculosis the problem had been actively investi- 

 gated before Wright, and there seems little question that tuberculin 

 therapy properly and cautiously applied has an established value in 

 the treatment of initial and localized tuberculous disease. Whether 



51 See also Theobald Smith, Jour. A. M. A., Vol. 60, 1913, and R. M. 

 Pearce, Jour. A. M. A. } Vol. 61, 1913. 



32 For discussion of various clinical applications of vaccine treatment 

 see symposium on vaccine treatment, Trans, of Ass'n of Amer. PTiys. and 

 Surg., Vol. 8, 1910. 



