340 UNIVERSITY OF COLORADO STUDIES 



diazo reaction allows ua to make a certain differential diagnosis be- 

 tween a recurrence and a secondary fever brought about by other 

 causes. 



The question often arizes, does the intensity or duration of the 

 reaction correspond with the severity or length of the fever? We 

 answer in the affirmative as to the duration of the reaction. If a 

 patient with the clinical symptoms of typhoid fever comes under our 

 observation toward the end of the second w^eek of the disease and 

 diazo is absent, the chances are that the infection is on the decline 

 and we prognose a mild course. If, on the other hand, the diazo 

 continues and increases in intensity, the case is liable to be prolonged 



and more serious. In our series of cases the diazo continued loncrest 



o 



in the patients who were sick longest and whose symptoms were 

 most pronounced. According to Ehrlich, the reaction first appears 

 between the second and sixth days, and disappears usually during 

 the first days of remission. In a case of typhoid fever which Dr. 

 Dock was able to follow from the first day of the disease the diazo 

 reaction was present for the first time on the fifth day. In one of 

 our cases it was also present as early as the fifth day. 



To illustrate the constancy with which this reaction is present 

 in typhoid fever I will give the statistics of different investigators. 

 In my series it was present in 19 out of 22 cases. Ilewetson found 

 it in 136 of 196 cases examined in Osier's clinic. The combined 

 cases of Ehrlich, Spiethoff, Brecht, Brewing, Paterson, Jez, and Nis- 

 sen number 178, of which 174 gave the reaction. Rivier has col- 

 lected 536, of which 520 gave the reaction. Gerhardt says that in 

 his clinic during a period of five years only one hona fide case of 

 typhoid fever, which was proved by post-mortem, failed to give the 

 diazo reaction. Zinn found the reaction in 75 per cent, of cases. 

 Clemens found it in 135 of 157 cases. Greene obtained a positive 

 result in 28 of 29 cases. Friedenwald found it in 20 of 21 cases. 

 Dawson found it in 44 of 85 cases. 



Out of a total of 82 of our cases of tuberculosis the diazo reac- 

 tion was found in 42. The number of tests made in each case varied 

 a great deal, inasmuch as a large number of the patients remained 



