Abstract
This paper is written from the practical point of view of a laboratory worker who is daily in direct contact with the cases submitted to him for diagnosis. Its purpose is to prove the inefficiency of the Widal reaction as a diagnostic test, and to urge its replacement by a more satisfactory method. Such a method is to be found in the application of the discoveries and theories on agglutination of Weil and Felix (1920), Felix (1924 and 1929), and Felix and Olitzki (1928 and 1929).