The authors made investigation on Abbott and Shannon's colicine typing scheme by means of colicinogenic strains used in the classification of colicines by Fredericq; the results were as follows.1. Colicines produced by each colicine type were; 1A=K, 1B=? 2=I, 3=?, 3A≈D 4=I, 5=? 6=E1, 8=E (3), 9=E (3), 10=?, 11≈K1+?, 12=E (3), 13≈E1, and 14=E1+I. Among colicine types which produce two different colicines, only type 14 coincided with the inhibition pattern of colicinogenic strain (CA 62=E1+I).2. As to the two unstable colicine types 4/14 and 11/6, type 14 produced colicine I and colicine active to E1, and type 11 produced colicine K and colicine active to E1. According to these facts, the transference of colicine types was frequently noticed.3. Colicinogeny of 272 isolated of Shigella sonnei had two different colicines, E1+I at the rate of 64.7% (type 14) and E1+I at the rate of 8.1% (type 4/14), colicine E1 at the rate of 20.5% (type 6), colicine I at the rate of 3.3% (type 4), colicine E3 at the rate of 2.2% (type 6), colicine E3 at the rate of 0.7% (type 8) and colicine K at the rate of 0.7% (type 1A).4. Abbott and Shannon's colicine typing method can be available even in the use of the mutants resistant to colicines.