486 PATHOGENIC BACTERIA. 



In addition to the 230 cases considered above, in which 

 the clinical symptoms and course were typical, we noted 

 the presence of the Widal reaction in 10 cases that were 

 atypical, and, apart from the presence of the sero-reaction, 

 so lacking in the characteristic typhoid features as to be 

 placed in the category of non-typhoid diseases. 



In a series of 300 cases taken from the records of the 

 Episcopal, Presbyterian, and St. Agnes' Hospitals, Dr. 

 W. H. Bell l found that the Widal reaction was unob- 

 tainable until the disease was well advanced, the average 

 in this series being the ninth day, and the earliest the 

 fifth day of the disease. 



Delepine 2 points out that during the first week the 

 reaction is often slow and not quite clear, and that to 

 establish an assured diagnosis a re-examination is often 

 necessary. 



The results obtained in Osier's wards in the Johns 

 Hopkins Hospital by Block and Gwyn up to Novem- 

 ber, 1898, show that in 151 cases the reaction was pres- 

 ent in 144. "In 4 of the negative cases the clinical 

 course was not certain. In only 46 of the last 108 cases 

 was the reaction obtained; in only 26 cases was the reac- 

 tion present before the seventh day of the disease ;" in 4 

 cases it developed on the twenty-second, twenty-sixth, 

 thirty-fifth, and forty-second days respectively. 



In a very few cases it is absent altogether. In this 

 connection it may be noted that there are cases in which 

 the reaction is missed during the primary attack, or until 

 the period of convalescence (Achard, Blumenthal), and, 

 in still others, it first makes its appearance in the relapse 

 (Biggs, Park, Stahl, Bell, et a/). 



In the American Year-Book of Medicine and Surgery 

 for 1898, Drs. Stengel and Kneass have collected and 

 tabulated, from the previous statistics of different writers, 

 2392 cases of typhoid, in which the reaction was positive 

 in 2283 and negative in 109. Also 1387 non-typhoid 



1 University Med. Mag., June, 1898. 



- Allbutt's System of Medicine, vol iii , p. 1147. 



