Viruses and Heterogenesis

Abstract

THE definition and nature of life have been favourite subjects for ancient and modern discussion. Sir Henry Dale, armed with many recent exact data, stated in the Huxley Memorial Lecture on “Viruses and Heterogenesis”, delivered at the Imperial College of Science on May 2 (London: Mac“millan and Co., Ltd. Is. net), the dilemma which confronts those who attempt to decide whether all the viruses which cause disease are self-propagating micro-organisms or whether some of them do not originate from the tissues of the host. Admitting that their minute size is perhaps the most important obstacle to accepting the smallest viruses as frankly living, he pointed out that there is an unbroken series from a virus of about the same size as the smallest bacteria with a diameter of 750 mpi to the virus of poliomyelitis estimated at 10 nipt,, which approaches the size of a protein molecule; the diameter of a molecule of egg-albumin has been calculated as 4-33 mpt. (1 m(jL = one millionth of a millimetre). The long category of viruses has several characters in common, making it very difficult to draw an arbitrary line at a certain size as criterion for separating two classes of entirely different natures.