Cultures ofSerraliaeven when unpigmented can be identified by their flagella which have an unusual coiled shape.Serratiacultures isolated from clinical materials are lactose negative, imvic − − + +, sulphide negative, anerogenic, and have a distinctive pattern of fermentative abilities. A differentSerratia, not so far encountered in clinical materials, is also described. The literature on isolation ofSerraliafrom man and animals is summarized.