The Morphology of Filterable Viruses

Abstract

THREE brief papers in the December number of the Journal of the Royal Microscopical Society by J. E. Barnard, J. Smiles, and F. V. Welch, discuss the great difficulties of determining the outward forms of the filterable viruses, and some contribution is made towards improved methods of attack. Mr. Barnard states that all ordinary bacteria may be stained and their size and form demonstrated if they are not less than 0.2 μ in diameter. The virus of bovine pleuropneumonia, which can be definitely and readily grown in artificial media, comes within this limit, but its minute size has precluded any satisfactory knowledge of its real appearance and of any possible phases through which it may pass in its growth cycle. Staining processes, moreover, have not helped matters.