The Serologic Diagnosis of Pullorum Disease in Domestic Fowls

[摘要] In the first part of this paper experimental results concerning constancy in agglutinability of three strains of Bact. pullorum are given. It is shown that the usual variations in the cultural conditions such as temperature, original pH of the agar medium and frequency in transferring cultures have less influence on agglutinability than the final pH of the culture antigen and the temperature at which the agglutination is conducted. Antigens adjusted to pH 6.4 and to pH 8.0 were more agglutinable than the same antigens adjusted to pH 7.0. At 37°C. the rapidity and degree of agglutination were much greater than at 16°C.Attempts to select daughter strains of different agglutinability were unsuccessful, indicating further that the strains with which these studies were conducted are remarkably constant in their agglutination property.The factors influencing and causing the so-called “cloudy” reaction were studied. It was found that by employing phenol in concentrations of from 0.2 to 0.3 per cent and adjusting the H-ion concentration of the antigen to pH 8.2 to 8.5, the formation of the flocculent precipitate was prevented. At this H-ion concentration the bacteriostatic action of the phenol (0.2 to 0.3 per cent) is apparently complete. The suppression of the pH by sera which tend to produce “cloudy reaction” when added to the agglutination fluid is reported here apparently for the first time.Antigens adjusted to a definite pH by means of alkali or buffer should find general application in the elimination of interference in the routine agglutination test by the so-called “cloudy” reaction.

[学科分类] 生物科学（综合）