Attenuated Infection: The Germ Theory in Contemporary Perspective by Harold J. Simon (review)

Abstract

transfer studies in Amoeba (Danielli). All the articles are worth reading, some are stimulating , and the volume is, in general, recommended. Variation among the authors' precision in writing is notable. One can wonder about the value ofreferring to "transduced characters" and "transduced clones," as one author does (and in the same sentence). The considerations by Pritchard ofrecombinational analysis are probably the most analytical in the volume; he reports interesting observations which support the hypothesis that homologous contact between chromosomes is a limiting factor in recombination. For the person with a general interest in genetics, this volume will be a helpful up-to-date summary, and for the specialist in this area, necessary reading. M. L. Morse University ofColorado Attenuated fofection: The Germ Theory in Contemporary Perspective. By HaroldJ. Simon. Philadelphia: Lippincott & Co., i960. Pp. xvi + 349. $10.00. The period 1950-60 witnessed a revival and extension ofthe perspectives to infectious disease which were earlier promulgated by Charles Nicolle and Karl F. Meyer. The concept ofinfection without disease as a particular phase of a host-parasite relationship has been widely attended by virtue ofthe variety ofstudies directed toward a better understanding ofnatural resistance. It was inevitable that a new surge ofinterest would follow the many observatons that cells ofpresumably healthy hosts harbored infective agents, whether these agents be bacteriophages, plant or animal viruses, or bacterial or protozoan forms. Activation of silent infections—or as Simon prefers to term them, "attenuated infections"—by hormones, drug dierapies, irradiation, or a host ofodier activating procedures ^—has fostered the view that die state ofinfection is a much more normal condition in nature dian the state ofinfectious disease. Simon argues that the infection state is an almost universal condition in nature. He has written a comprehensive exposition of this thesis ofaberration in the form ofovert infectious disease. By the most far-ranging excursions into all areas ofbiological interaction at different levels ofintegration, Simon provocatively organizes the data on attenuated infection, or coexistence, into the subcategories of latency, microbial persistence, and the carrier state, depending upon the particular qualities of die parasite at the time it is isolated from the host. It is not the easiest classification to use experimentally, because it is difficult to assign relative weights to die altered qualities which the parasite may possess in one or another ofthese infection states. The uniqueness ofthis work lies in its interdisciplinary approach and the breadth of scholarship, which is reflected by the author's success in synthesizing a very coherent description ofthe various levek on which host and parasite may come to equilibrium.The privilege ofhaving for this purpose over 300 pages in which to make the case would have been morejustified ifthe actual sets ofdata needed to document the arguments had been included in the text. A minor point on which I would take issue with the work is the lack ofclarity concerning which aspects of the "germ theory" are in question or need refinement. The 383 main thesis is that, while the etiologic agent may be present, there are predisposing factors which act to allow the parasite toexploit its presence. The concept ofdieliving agent ofdisease is obviously not in question, but the concept ofthe specific element certainly is—that is, the weight to be attached to the specificity aspect in the causation ofinfectious diseases. The organization ofthe book is excellent. After certain necessary redefinition ofterms is accomplished and the scope ofthe thesis is laid out, Dr. Simon surveys the breadth of occurrence ofattenuated infection in nature through the animal and plant kingdoms and through the variousphyla ofplant and animalparasites. Atthis pointadiscussionofmeans ofunmasking the latent or silent infection in living cells is followed by a comprehensive review ofthe various mechanisms and factors operating in all varieties ofhosts to affect the fulfilment of the infectious process. To some, but not entirely a rewarding, extent the phenomenainvolved in mixed infection are analyzed with reference to synergism and antagonism; but veryingenuous treatment is given to those situations. Perhaps leastwell treated are the implications in lysogeny and the consequent induction oftoxin-forming ability. A delightful introduction to socio-medical and politico-medical problems as they bear upon respiratory troubles and air pollution as well as radiation illness and modern...