MASTERING THE MICROBE 



dotes, with the result that a residual quantity of 

 typhoid antitoxins and bactericides, and agglutinins, 

 and opsonins, finding no further host of enemies at 

 hand, passes into the general circulation and becomes 

 a relatively permanent constituent of the blood serum 

 and lymph. 



It is in the production of this excess quantity of 

 the antidote to a given bacterial poison that the en- 

 tire rationale of artificial immunization consists. For 

 now let us suppose that the individual thus treated 

 chanced accidentally to ingest some living typhoid 

 germs in his food or drink. These germs as they 

 enter his blood are at once met by the anti-bodies 

 already there, and are promptly destroyed; whereas 

 in the body of a non-immunized subject, they would 

 have multiplied so rapidly that the tissues could not 

 have adequately met them with the production of 

 antidotes. 



THE NEW METHOD IS RIGIDLY SCIENTIFIC 



The value of the preventive inoculation against 

 typhoid has been fully demonstrated. The British 

 Army used the anti-typhoid vaccine in the South 

 African war. Then it was introduced into the Ger- 

 man army, and used by the American army in the 

 Philippines. Very recently its use has been made 

 obligatory in the American army, and it has been 

 used effectively to check epidemics of typhoid fever 

 among civilians, as at Salt Lake City. An inkling of 

 the importance of this discovery from a merely eco- 

 nomic standpoint may be gained if we recall that the 

 annual cost of typhoid in the United States has been 



213 



