SIGNIFICANCE OF PHENOMENON 375 



irregular or no neutralization Avith 5 units of active principles 

 of the other three meningococcus groups. This netUralizing po- 

 tency dexeloped in the course of the disease, since serum from 

 early bleedings did not neutralize as well as that from later bleed- 

 ings. It apparently was due to some common antigenic component 

 present in the etiologic microorganism in this case and in Group 

 I meningococcus. It should be also noted that serum "J. C." ob- 

 tained from a patient convalescent from meningococcus menin- 

 gitis, possessed capacity to neutralize both meningococcus and 

 gonococcus reacting factors. 



NEUTRALIZING POTENCY OF SERA FROM TYPHOID INFECTIONS 



A good opportiuiity to determine the possible importance of 

 B. typJiosus neutralizing antibodies was afforded by studies on 

 patient S. T. This patient, aged t^venty-four, contracted typhoid 

 fever tAvo ^veeks before admission to the hospital on May 1 1, 1932. 

 At home he had been delirious and stuporous, requiring cathe- 

 terization for urinary retention. Admitted in delirium, he had, 

 in addition to rose spots and a large spleen, a left epididymitis. 

 The temperature became normal two days after admission and 

 the patient ^vas well except for a silent typhoid bacilluria which 

 persisted for a month. B. typliosus ^vas recovered from the stools 

 once and from the urine three times. The Widal tests of the blood 

 for typhoid and paratyphoid ^vere negative. 



Serum from ^veekly bleedings ^vas titrated for potency to neu- 

 tralize B. typhosus reacting factors. 



In addition, the sera of 5 patients who had had typlioid fever 

 within the previous fe^v years and of 4 controls (patients a\ ith no 

 history of typhoid fever) ^vere titrated for capacity to netitralize 

 B. typhosus reacting factors. It is of considerable interest that in 

 these tests the capacity of serum of patient S. T. to neturalize B. 

 typhosus reacting factors rose from no neutralization of 25 

 tmits on May 23rd to complete neutralization of 75 tmits on 

 Jinie 16th. Control experiments on neutralization of meningo- 

 coccus reacting factors remained unaltered for the same period 

 of time. The residts, therefore, indicate that the acquired neutral- 

 izing potency was specific for B. typhosus. Incidentally, it should 

 also be noted that in patient S. T. the Widal tests remained con- 

 sistently negative, and, therefore, the sole demonstrable evidence 

 of antibody response developing with recovery from typhoid in- 

 fection was the increase in the capacity of the serum to neutralize 



