This study was conducted on the suggestion of Dr. Thorvald Madsen following a meeting in 1932 of the cholera committee appointed by the Office international d'hygiène publique, at which was discussed the problem of producing a standard cholera agglutinating serum for diagnostic purposes. A study was made of 384 strains collected from districts where cholera and cholera-like diseases are epidemic. Biochemical as well as agglutination tests have been made with these strains. The author concludes that at the present time it does not seem possible to produce a standard agglutinating serum, since many vibrios termed cholera-like have not been demonstrated to be pathogenic or to produce the clinical picture called Asiatic cholera. This work contains forty-three tables and a good bibliography.