Filterable Viruses

Abstract

THE nature of ‘virus’ still eludes precise definition. No one knows exactly what it is, and none of the hypotheses covers all the apparent facts without a certain amount of artificial straining. At one extreme there is the conception that a virus is a parasite, something analogous in a general way, though not necessarily closely similar to a bacterium or a protozoon, with properties appropriate to its very small size. It is odd, though, if this is so, that no saprophytic virus is known. We can imagine a pathogenic bacterium arising by some process of adaptation from the many similar saprophytes existing everywhere in Nature, but the viruses are always associated with living cells and have never been certainly known to multiply in their absence. At the other extreme are those who look upon them as derivatives of the cells with which they are associated, possibly particulate but not living individual organisms. The difficulty in this view is to explain the transmissi-bility, the remarkable power of multiplication or increase, and the specificity revealed by serological reactions.

Filterable Viruses.

Harold L. Amoss Jacques J. Bronfenbrenner Alexis Carrel Edmund V. Cowdry Rudolf W. Glaser Ernest W. Goodpasture Louis O. Kunkel Stuart Mudd Peter K. Olitsky Thomas M. Rivers. Thomas M. Rivers. Pp. ix + 428 + 15 plates. (London: Baillière, Tindall and Cox, 1928.) 34s. net.