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• A test for typhoid fever, performed by adding 1 part of blood serum of a suspected case to 24 parts of distilled water and adding 1 platinum loopful of this mixture to a 24 hour motile peptone culture of the typhoid bacillus on a clean cover slip. This is placed drop downwards in a hollow glass slide and usually during some part of the course of the disease, the diluted serum of a typhoid patient will cause agglutination or clumping of the bacilli with cessation of their motility. This is called a positive reaction for typhoid fever.

1916 - Appleton's medical dictionary
By Smith Ely Jelliffe