The lethal dose of the toxins of four anaerobes has been ascertained in mice, sheep, and in two instances in guinea-pigs also. The mouse : kilogram-body-weight-sheep ratio is as follows:
Cl. septique 1:17.5, Cl. welchii, Type B 1:60, Cl. welchii, Type D 1:12.5 and Cl. oedematiens 1:100. The last ratio was arrived at by the use of only six sheep and is thus approximate.