“…BECAUSE known fecal pathogens fail to ferment lactose, investigators are predisposed to regard late lactose fermenters with suspicion. Consequently many workers have recorded a paracolon bacillus as the causal organism of the disease manifested by the patient (Castellani, 1912(Castellani, , 1914(Castellani, , 1917Spaar, 1915 ;Lurie, 1916 ;Castellani and Chalmers, 1920 ;Hassmann and Herzmann, 1934 ;Hassmann, 1935 ;Kriiger, 1941). Since all non-lactose-fermenting colonies must be investigated in cultures from patients with enteritis, it is not surprising that the literature on paracolons in association with authentic cases of dysentery is considerable (Fildes, 1917 ;Dean et al, 1917 ;Dobell et al, 1918 ;Sandiford, 1935 ;Adams and Atwood, 1944).…”