The Reduction of Nitrates to Nitrites by Salmonella pullorum and Salmonella gallinarum

The results of investigations dealing with the ability of Sal-monella pullorum and Salmonella gallinarum to reduce nitrates to nitrites in a nitrate-peptone solution do not agree. Rettger and Harvey (1908) reported reduction by both organisms. Bush-nell, Hinshaw and Payne (1926), Kaupp and Dearstyne (1927), Wallace and Neave (1927), and Tittsler (1928) reported reduction by Sal. pullorum. Hadley, Elkins and Caldwell (1918) found no reduction by either organism. Gage (1922), and Hadley, Caldwell, Elkins and Lambert (1917) reported no reduction by Sal. pullorum. Kaupp (1927) states that nitrates are reduced by Sal. gallinarum but not by Sal. pullorum. Bergey's Manual (1925) characterizes both organisms as negative to the nitrate test. Mallmann (1925) in an extensive study of Sal. pullorum found considerable variation. In 1924 his cultures gave a "weak positive test, " but in 1925 some "were strongly positive, while others were weakly positive " and still others "were positive in only one tube. " Perhaps the differences in results were due to differences in the media or methods of testingfor nitrites; however, no definite conclusions can be drawn since no statements were made concerning these points except in the reports of Wallace and Neave (1927) and Tittsler (1928). The assumption that a "Standard Nitrate-Peptone Solution " was used would be errone