488 



PATHOGENIC BACTERIA. 



confirm the observations already quoted, 

 were students, nurses, and physicians. 



Most of these 



Studies of the Blood of 30 Cases Convalescent from Typhoid 

 Fever for Varying Lengths of Time, Illustrating the Dura- 

 tion of the Widal Reaction : 



Time since convalescence. 



I month G 



6 months D 



18 « Dr. R 



1 year F. S. C 



2 years H 



9 

 9 

 9 

 13 

 14 

 15 

 15 

 16 

 16 



17 

 18 

 20 



S. . . . 



c 



G 



L. C. S. . 

 Miss P. . 



S 



B 



R. W. . . 

 R. . . . 

 Mrs. McB. 



J. R. . • 

 M. . . . 

 A. D. . . 

 Miss W. . 



I 



W. J. R. . 

 Stern. . . 

 Miss F. . 

 Miss J. . . 



D 



O. B. R. . 



B 



M. . . . 



P. . . 



S. P. H. . 



Reaction. 



+ 

 + 

 



+ 



+ 



O 



+ 



o 



+ 

 o 



+ 

 + 



O 



+ 



O 



+ 

 o 



+ ? 



O 

 O 



+ ? 



O 



o 

 o 



O 

 O 



o 

 o 



O 



o 



One person, not included in the table, suffered from two attacks of typhoid 

 fever, one eight, the other thirteen years ago. At present the blood does not 

 possess any reactive power. 



When once established the reaction is usually constant; 

 but occasionally cases are observed in which it is absent 

 for short intervals, usually during the period of its estab- 

 lishment or disappearance. 



