750 INFECTION AND IMMUNITY. 



demies have occurred in the Faroe Islands and in 

 Iceland, with a mortality exceeded by few epi- 

 demic diseases. 



A moderate leucocytosis is excited in measles, 

 "which begins soon after infection, reaches its 

 maximum six days before the appearance of the 

 eruption, and lasts into the first part of the stage 

 of invasion" (Tiliston). We are ignorant of the 

 significance of this leucocytosis, 



There is no serum therapy for measles. Weiss- 

 becker states that the serum of convalescents in- 

 fluences the course of the disease favorabl. 



XI. GERMAN MEASLES 



Rotheln is considered as distinct from measles, 

 in spite of clinical similarities. It is recognized 

 because of certain peculiarities in the eruption and 

 its uniformly mild course. Perhaps the strongest 

 reason for believing the two diseases to be distinct 

 lies in the fact that an attack of rotheln does not 

 leave an immunity against measles. 



Rotheln is contagious. Efforts should be made 

 to prevent extension, as in measles, the methods of 

 transmission being the same in the two diseases. 



XII. WHOOPING COUGH. 



Various protozoa (?) and bacteria (cocci and 

 bacilli) have been assigned as the cause of whoop- 

 ing cough. Many of the so-called protozoa found 

 in the throat were undoubtedly tissue cells (leuco- 

 cytes, ciliated epithelium). Among the cocci, the 

 diplococcus of Ritter (1892) acquired some promi- 

 nence. He is said to have found it constantly in 

 146 cases. Investigations by others failed to jus- 

 tify his conclusions. 



