| Notas: | "This", as the author states in his preface to the first edition (1939), "is not meant to be a textbook of virus diseases" and consequently, as an examination of the subject-index and the two chapters on Symptomatology confirms, it cannot be expected to function as a diagnostic handbook for practising plant pathologists. Mr. Bawderi is here primarily concerned rather with his own particular research approach, the study of the viruses qua viruses, preponderantly of those infective isolates from virus-diseased plants the properties of which can be studied in vitro, and the bulk of the book is concerned with reviewing in impressive detail the considerable recent contributions of scientific workers in fields other than that of plant pathology, namely " chemists, crystallographers, entomologists, geneticists, serologists, physicists and others ", and as such provides an invaluable compendium of information for the research virologist. A brief synopsis of chapters will sufficiently indicate the scope of the work. I. An Introductory Survey is followed by a general account of Symptomatology, both external and internal (II and III). IV is a survey of methods of Transmission, and V Relationship between Viruses and their Insect Vectors, enlarged in the present edition to include recent work on this subject of important application to the analysis of virus complexes. VI, Virus Strains, Mutations and Acquired Immunity, is of considerable relevance to the problem of economic control. The next seven chapters (120 pp.) deal with studies of virus isolates in vitro, namely VII, Serological Reaction of Plant Viruses; VIII, Methods of Purification; IX, Properties of Purified Virus Preparations; X, Optical Properties of Purified Virus Preparations; XI, Inactivation of Viruses; and XII, The Sizes of Virus Particles. This section is followed by a chapter XIII on the Physiology of Virus-Diseased Plants. The work concludes with XIV, The Classification of Viruses, XV, The Control of Virus Diseases and finally XVI, Discussion on the Origin and Multiplication of Viruses. The picture thus presented of " these intriguing pathogens " is necessarily incomplete, for, unlike such pathogens as fungi and bacteria, a complete concept of any virus as an entity cannot yet be disentangled from its obligate living plant environment. Thus, whilst Mr. Bawden in his preface to the present edition states that "most workers are agreed that tobacco mosaic virus is a nucleo protein ", it will be appreciated that this conclusion is based on the study in vitro of an infective isolate from mosaic tobacco plants which, although able to reproduce the disease on re-inoculation, has proved to be quite inert outside its living host. True, as Mr. Bawden suggests, a castrated dog is still a dog and possibly a living dog, but with the lack of even one virus culturable outside its host it is extremely problematic, under existing visual limitations, just how closely and in what respects the isolated " virus " approximates to the total virus existing and multiplying within the living plant cells. In this connexion Mr. Bawden in his new preface and in his closing chapter stresses the present lack of knowledge of " the behaviour of viruses in their natural environment within the host plant ", i.e. in vivo, and predicts that the next major advances in the subject will concern this important aspect. |
|---|