THE BACILLUS OF WHOOPING-COUGH. 481 



children of the same age (4 years), both of whom were convalescent, 

 one of whooping cough and the other of bronchopneumonia follow- 

 ing scarlet fever. As a result, 0.2 of a cubic centimeter of the 

 serum in the first case sensitized the whooping-cough bacillus and 

 produced alexin absorption. The subsequently added sensitized 

 corpuscles remained intact, whereas hemolysis took place in 5 

 minutes in the mixture containing the other serum. 



As we regard the facts in the etiology of whooping-cough as well 

 established, we shall hope to announce soon the results of attempts 

 at serumtherapy or active immunization which we have made. It 

 may be mentioned in this connection that the injection of a cubic 

 centimeter of culture, killed by heating to 62 degrees,* produces no 

 unpleasant symptoms in man. 



* Heating to 55 degrees suffices to kill the organism. 



