The "Brownian movement" was first described in 1828 by the botanist Robert Brown. While investigating the pollen of several different plants, he observed that pollen dispersed in water in a great number of small particles which he perceived to be in uninterrupted and irregular "swarming" motion. For more than half a century following, a score of scientists studied this motion, common to organic and inorganic particles of microscopic size when suspended in a liquid, to determine the causes and the dynamics of the motion.This volume contains five papers investigating the dynamics of this...

R. VANFURTH Infection is an inseparable part of communal life, and infections are more common and more severe in hospital communi ties because the sick are more easily infected than the healthy. However, even though progress in the medical sciences has meant that many more patients suftering from relatively severe diseases can be helped at present, the use of more sophisticated and complex treatment leads to impairment of the defence mechanisms in more patients than was the case ten to twenty years ago, and these patients are also more prone to develop an infection. Two questions are...

Recent reviews of respiratory-tract affections caused by M. pneumoniae under- score the benign and often subclinical course of the infection. Severe pneumonia with a reticular or acinar pattern is certainly unusual and a fatal outcome is rare, but the incidence of both is underestimated. Erythromycin and tetracyclines are the first-choice antibiotics. There is evidence indicating the importance of im- munopathogenic mechanism in provoking pneumonia and even respiratory failure. REFERENCES 1. Krech U, Price PC, Jung M: The laboratory diagnosis and epidemiology of mycoplasma pneumoniae in...