A. Bonnefoi

Essai de classification biochimique et sérologique de 24 souches deBacillus du typeB. Thuringiensis

Summary24 strains ofBacillus thuringiensis type are studied by the determination of 35 cultural and biochemical characters. About 10 different biochmeical characters make it possible to classify these strains into six major biochemical groups represented by one or two type-strains (biotypes). On the other hand, the study of these 24 strains by the flagellate agglutination reaction also leads to six serological groups, each one provided with a different H antigen, and which fit perfectly the biochemical classification. This fact emphasizes the validity of this latter classification and, for the first time, brings in a double biochemicals-serological basis for the classification of theB. thuringiensis type strains.

Recherches sur l'action des cristaux deBacillus thuringiensisBerliner souche «Anduze»

SummaryThe researchs of different authors on the conditions of the pathogenous effect ofBacillus thuringiensis are rewied with special reference to the toxicity of the crystal bodies which appear during the sporulation.Pure extracts of crystal obtained by theAngus method were tested by the technic ofBurgerjon. Pure crystals are 2,5 times more active than the standard preparation ofB. thuringiensis. Spores from which the crystals are removed have no toxicity.The works ofHeimpel are discussed at the light of this study: to-day it appears that the toxemy is caused by the crystalline protein in the caterpillars with intestinal pH>9; other toxical possibility of the germ may appear by influence of others conditions.

Essais de thermorésistance de l'organisme responsable de la maladie laiteuse de la Larve du Hanneton (Melolontha melolontha)

SummaryThe organism responsible for the milky disease of the cockchafer (Melolontha melolontha) when diluted in distilled water and heated for 1 hour at 84°C retains its infectivity. However this temperature diminishes the vitality of the organism, in order to eliminate the saphrophytic organisms of the haemolymphe, it is preferable to heat to use a temperature of 75°C.