The 198 strains of Clostridium perfringens isolated from fishes were tested whether they serologically agree with Hobbs' Types. The results obtained from the experiments are as follows.
1) The 32 strains (16%) of isolated Cl. perfringens 198 strains were in agreement with Hobbs' Types in agglutination test, that is, Type 2-2 strains, Type 3-one strain, Type 4-8 strains, Type 5-7 strains, Type 6-one strain, Type 8-one strain, Type 9-7 strains, Type 12-one strain and Type 13-4 strains were detected (Table 1).
2) The 11 strains belonging to Hobbs' Types, although they came in small numbers, were detected in heated (80°C, 20min) specimens. Moreover, heat-resistant (100°C, 60min) Hobbs' Type strains, namely the 5 strains from body-surface specimens of fishes and the one strain from alimentary canal specimens of those were selectivery isolated by applying the heat-treatment (Tables 1 and 2).
3) In unheated specimens, Hobbs' Type strains were detected, in a low percentage through the period from June to September (Table 3). However, every one of the 21 strains (18 strains from body-surface and 3 strains from alimentary canal) identified as Hobbs' Type strains did not possess heat-resistance in cooked meat cultures (Tables 1 and 2).