20 MODERN BIOLOGIC THERAPEUSIS 



Widal and Sicard; the diagnostic use of tuber- 

 culin by Calmette, von Pirquet and Moro 

 (1907) ; Sir Almroth Wright's preventive inoc- 

 ulation against typhoid fever by killed cultures 

 of the bacillus (1900) ; Abderhalden's enzyme re- 

 action in the diagnosis of pregnancy (1912) ; 

 and the principle of filterable viruses. 



