THE BACILLUS OF WHOOPING-COUGH. 613 
not yellow fever. According to them the lungs were 
the earliest and the chief seat of the lesions. Their 
report adds to the mystery of the effect of cold on 
stopping the spread of the disease, for nearly all respi- 
ratory diseases due to bacteria tend to increase in cold 
weather, and certainly their spread is not stopped im- 
mediately. This bacillus can as yet be considered as 
only the possible cause of yellow fever. 
THE BACILLUS OF WHOOPING-COUGH. 
From time to time observers have found in the 
sputum of persons suffering from whooping-cough 
small bacilli, often in great numbers. These have been 
studied lately especially by Koplik’ and Czaplewski? 
and Hensel, who believe that these bacilli are the cause 
of the disease. They are small bacilli of about the size 
of the influenza bacillus, and grow on blood-serum and 
nutrient agar in tiny colonies. Mice and rabbits. die 
after intravenous inoculations. No symptoms similar 
to those in man are noted. The observers differ as to 
the description of the bacilli, and those interested are 
referred to the original articles. The examination for 
these bacilli, if they prove to be the true cause of the 
disease, may prove of diagnostic importance, and also 
be of use in detecting sources of contagion. 
1 Centralblatt fiir Bact. Abth., 1 Bd. 22, p. 222 2 Tbid., p. 641. 
