TYPHOID FEVER. 487 



cases, of which 22 reacted positively and 1365 negatively. 

 The results in these cases show — 



Reactions in typhoid cases 95.5 per cent. 



No reactions in non -typhoid cases 98.4 " 



Correct results in . 96.5 '* 



Incorrect results in 3.5 " 



Surely, this table indicates a small proportion of nega- 

 tive responses. 



II. The duration of the reaction is by no means con- 

 stant. In the greater number of cases the agglutinating 

 property of the blood begins to diminish in the first 

 weeks of convalescence, and marked reduction in its 

 activity is noticed in a few months. Few cases continue 

 to show it longer than one year. Widal and Sicard 1 

 found that it sometimes disappears as early as the eight- 

 eenth day after convalescence. Brenner saw it disap- 

 pear on the seventeenth day in one case and on the 

 twenty-fifth day in another case. E. Fraukel found it 

 absent after the twenty-eighth day in one case. In all 

 the cases observed by Widal and Sicard the reaction dis- 

 appeared within a year. Sometimes, however, the reac- 

 tion has been observed to persist much longer, and in a 

 series of cases which had had typhoid fever a varying 

 number of years before the examination, Widal and 

 Sicard found it still present in one case 3 years after 

 recovery, in one case 7 years after recovery, and in 

 another 9 years after convalescence. Widal tested 80 

 cases of typical or suspected typhoid fever at periods 

 ranging from 1^ to 9 years after convalescence, obtain- 

 ing 6 positive and 16 negative results. Musser and Swan 2 

 found that in their series of cases the reaction disappeared 

 in one case on the thirty-eighth day, while in one other 

 case it persisted for ten years. 



I was much interested in the following series of 30 

 cases which show the persistence of the reaction and 



1 Compt. rendu de la Soc. de Biol., Dec. 1 9, 1896, No. 33. 

 * Journal American Med. Assoc, Aug. 14, 1897. 



