THE EHKLICH DIAZO REACTION 343 



Three of the cases of tuberculosis in which the diazo was nega- 

 tive were cases of peritoneal tuberculosis. One of the cases in which 

 it was negative was tuberculous meningitis and miliary tuberculosis. 

 In one case of peritoneal tuberculosis the diazo was positive. In one 

 case in which there were both pulmonary and peritoneal tuberculosis 

 the diazo reaction was positive. 



The differential diagnosis between cirrhosis of the liver and 

 tuberculosis of the peritoneum is often difficult. The presence of 

 this reaction favors tuberculosis, but does not assist in excluding 

 cancer or sarcoma of the peritoneum. 



In measles, statistics show the reaction to be very constant. 

 Combining the statistics of Brewing, Brecht, Fisher, Nissen, Rivier, 

 and Clemens we have ninety-eight cases in which there were only 

 twelve negative. Michaelis uses this reaction as a means of differ- 

 ential diagnosis between measles and German measles, it being 

 absent constantly in the latter. The reaction lasts about live days. 

 In two of my cases of measles and several cases of German measles 

 the reaction was absent. 



Typhus Fever. Fischer found it in three cases; Dawson in live 

 out of ten cases. 



Scarlet Fever. Of eighty-seven cases from Berwing, Nissen, 

 and Clemens thirty gave the reaction. In three typical cases of 

 moderate severity I never found diazo. 



In thirty-three of our cases of carcinoma it was present in live. 

 Michaelis believes that in these cases it is due to a secondary infection, 

 as, for instance, an ulcerating carcinoma and similar processes with 

 bacterial infection. 



Erysipelas. In a case with very extensive lesions originating 

 at the site of drainage wounds and extending over almost the entire 

 body, I was never able to find diazo. Clemens reports five positive 

 cases in one hundred and twenty-two. Coste found the reaction in 

 two -thirds of his cases. 



The results of ray observations have been to confirm in most 

 particulars the statements of Ehrlich. They also agree with results 

 published from this laboratory in 1898 by Dr. Warthin. The fact 



