(Differentiation - molecular and cellular aspects) is of direct significance to develop- 

 mental biologists. It contains 1 1 reviews and research reports. 



Of the former we mention Cellular and tissue differentiation of mesenchyme (Robert 

 and Robert), Collagen biosynthesis and its regulation (Frey), and Interactions between 

 sclerotome and periaxial extracellular material in vertebral cartilage differentiation (Stru- 

 del). The following research reports may be mentioned: Synthesis and secretion of 

 collagen by fibroblasts (Frey et al), Differentiation of elastic tissue in the aorta (Courtois 

 et ai), and Tooth morphogenesis and cytodifferentiation in vitro (Ruch and Karcher). All 

 these papers are in French but all have Enghsh summaries. 



Collection of papers 



101. 



I. GERSH, ed. 1973. SUBMICROSCOPIC CYTOCHEMISTRY 



Academic Press, New York, etc. 2 vols. 



Vol. I Proteins and nucleic acids. XXIV, 388 pp., 351 figs., 4 tabs., author and subject 



indexes. $ 35.00 



Vol. II Membranes, mitochondria, and connective tissues. XVI1I,245 pp., 192 figs., 



6 tabs., author and subject indexes. $ 22.00 



This book is not a treatise but rather the report of an extensive and very original 

 project carried out by the editor and his associates over a period of more than a dozen 

 years. It started with the introduction of new methods for rapid freeze-drying of cells 

 followed by postfixation and staining by means of reagents in the vapour phase. These 

 techniques were subsequently appUed to a great variety of biological material. The studies 

 reported in this book centre on two main topics: morphological aspects of genetic control 

 in the nucleus, and the role of the cell in the formation of extracellular components. The 

 approach is largely cytochemical, but with a strong emphasis on morphology. 



Vol. I deals mainly with distribution patterns of nucleic acids in relation to protein 

 synthesis (particularly the conformation of DNA in first-, second- and higher order helices 

 and its association with the nuclear membrane). It is perhaps of most interest to 

 developmental biologists, because the findings and the conclusions (and informed specula- 

 tions) based on them have a profound bearing on the problem of gene regulation (at a 

 relatively coarse level) in determination, cell heredity, differentiation, and cell matura- 

 tion. This work surely begins to fill the gap between prokaryotes and eukaryotes, and it is 

 surprising that this was possible by meticulously applying an essentially morphological 

 approach! In vol. II most of the emphasis is on the molecular and macromolecular 

 organization of (particularly internal) membranes, and on the origin and distribution of 

 the major macromolecular aggregates of connective tissue. 



We briefly enumerate here those of the materials studied which are of particular 

 interest to developmental biologists: Drosophila syncytial blastoderm, Z)raiO/;/!//a salivary 

 gland, Drosophila imaginal discs, various differentiated and developing mouse cell types, 

 metaplastic mouse vaginal epithelium, cat spinal ganghon cells during nerve regeneration 

 (all in vol. I); epiphysial chondrocytes of rat tibia, rat cartilage matrix (in vol. II). Vol. II 

 is concluded by a chapter by Gersh entitled Summary, synthesis, and speculations. All 

 25 chapters have a brief summary. 



The books are beautifully produced and illustrated mainly with a profusion of superb 

 light and electron micrographs, supplemented by explanatory line drawings. 



227 



