The Cell Biology of Hydra

This slim monograph contains the author's research observations on the Hydra and a review of the work of other investigators. It presents a brief historical account of early work on the Hydra, particularly that of Trembley, followed by a brief description of the anatomy and physiology based on light microscopy, and a short account of the growth and regenerative capacities of the Hydra. The second chapter is a presentation of enzyme histochemistry as studied by the author in normal and regenerating animals; much of this material has been published before. The following six chapters deal with the fine structure of specialized cell types: the epitheliomuscular cells, digestive cells, gland cells, interstitial cells, cnidoblasts, and cells of the nervous system. The chapter on the gastrodermis contains some interesting observations on ferritin uptake by digestive cells and lack of uptake by epidermal cells; however, this material has also been published previously. Two chapters on the histochemistry of the nervous system and the neurology of regeneration provide information on neuropharmacological inhibitors, and are perhaps the most important contributions of the book. Although the book is clearly written, its general organizaton might have beein improved by combining the light microscopy descriptions with electron microscopy observations on cell types, instead of presenting the former separately. Fortunately, the last chapter brings together the observations and interpretations by use of several diagrams. There is a lack of audience consciousness throughout the book. It is not primarily for cell biologists. The electron micrographs are adequate, but often lack resolution, magnification, or contrast to illustrate details claimed in the text as identifying characteristics; for example, microtubules are not seen in ganglion cells (Fig. 138). Most of the concepts presented have been published with more insight by other investigators. The author restricts himself to the Hydra and thus any phylogenetic comparisons or more interesting generalizations are lacking or treated superficially. The book is not primarily for Hydra specialists, in that it goes over much ground covered in the excellent volume, The Biology of the Hydra and of Some Other Coelenterates, edited by Lenhoff and Loomis, University of Miami Press, 1961. For the specialist, the new material in this book might better have been presented as a series of articles, as much of it was. This material was more current wlhen published and underwent closer editorial scrutiny as regards substance, coverage of the literature, and typographic errors. The book may be of value, however, to the serious biology student who can gain factual information about the cellular organization of the Hydra as well as information on specific experiments well-designed to obtain data about cellular functions in the Hydra, which then may serve to extend our kniowledge and concepts of cells in all organisms.