Studies on respiratory infection: I. The influence of particle size on respiratory infection with anthrax spores

Experiments to determine the role of particle size in the infectivity of anthrax spores are described. Clouds of homogeneous particles were produced. The mortality-dosage curves for guinea-pigs and monkeys are given for clouds of various particle sizes. Data are given on the effect of time in the concentration-time relationship. The results are compared with those recorded by other workers on the relationship of particle size to respiratory retention. Infectivity was highest with single-spore clouds, falling off as particle size increased. Reasons are given for attributing this effect to difference in site of deposition of different-sized particles.