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Cajal on the cerebral cortex
Neuroscience Vol. 36, No. 2, pp. 569-570, 1990 Pergamon Press plc. Printed in Great Britain
BOOK REVIEW Cajal on the Cerebral Cortex (An Annotated Translation of the Complete Writings). By J. DE FELIPE and E. G. JONES. Oxford University Press, Oxford. 654 pp. $65.00. An English translation of the works of Ramrn y Cajal has been overdue for about 25 years. The volume entitled Cajal on the Cerebral Cortex is a great treasure even for someone having lived for half a century in close, almost everyday contact with the full series of the Revista Trimestrial Micogrdfica and the Trabajos del Laboratorio de lnvestigaciones Bioldgicas de la Universidad de Madrid, and the large collections of reprints gathered by the Hungarian admirers and "friends in arms" of Cajal: M. v. Lenhossrk, Karl Schaffer and D. Miskolczy. Now we can read the complete works of Cajal on the cerebral cortex in the translation of someone who has Spanish as his mother tongue without the fear of misunderstanding or misinterpretation. The authors have to be congratulated for their decision to present Cajal's papers chronologically in (I) an early period, (II) an "interlude", based mainly on the use of Methylene Blue supravital staining, (III) the middle period, covering the bulk or the hard core of the observations, (IV) the years of consolidation, when the material became synthetized in the large comprehensive books of Ramrn y Cajal on the nervous system, and (V) works from the "final years" (1921-1935). This puts the entire development of Cajal's understanding into its proper historical perspective, and gives the volume its real fascination. It reads almost as a modern bestseller of a mystery or detective novel, where one of the greatest stories of scientific discovery unfolds before our eyes-unfortunately only for those initiated in the neurosciences-a unique story as the accomplishment of a single demigod-like individual, comparable only with the great geniuses in art; figures like Leonardo, Shakespeare, or Mozart. An equally important asset of the volume are the carefully collected annotations, separately the notes given by Cajal and the authors', editorial notes. This feature renders this book a most valuable aid for anybody interested in the true history of the neurosciences. Also of particular importance are smaller chapters (e.g. Chaps 7 and 8), giving samples from Cajal's works during the years 1892-1894, containing most significant new insights about the general morphology of the pyramidal cells, an early and today well supported circuit model of a cascading connection between successively deeper positioned pyramidal cells, and--most signific a n t l y - a n essentially correct view of cortico-cortical connections with longitudinal (ipsilateral) and transversal (callosal) pathways. The applications by Ram6n y Cajal of the Methylene Blue stain to the cerebral cortex during the years 1896-1897 are very aptly listed in the volume as "An Interlude" and their crucial significance is correctly appraised. Using this stain, Cajal could convince himself and the majority of neurohistologists of the reality of the spineous dendritic appendages. Additionally, the characteristic differences between the spines in different neuron types is described exactly as it became known much later in electron microscopy (Fig. 48). It is only to be regretted that the delicate drawings of Cajal in blue colour of the original publications could not be reproduced in colour (for obvious cost reasons), because it is in these drawings that his unmatched power of observation and draftsmanship shows up to its greatest advantage.
One might go on and on through this excellent selection of Cajal's works on the structure of the cerebral cortex, and the development of his anatomo-physiological understanding of the cerebrum. The highlights of this long process are given in Chap. 25, and it is worthwhile for the contemporary student of the brain to retrace the road of Cajal's thinking three-quarters of a century ago; if it were only to see how little the changes are in our insight into the essentials, in spite of the explosive development in practically all fields of the neurosciences. Chapter 29 summarizing the final view of Cajal as reflected in his major last treatise: ~Neuronismo o Reticularismo? (1933) is treated rather briefly. But we cannot object to this, because the large part of this work is a defence of the neuron theory against renewed attacks by a new generation of reticularists. Only relatively little on the cerebral cortex appears in this, otherwise probably the most brilliant of Cajal's writings, apart from trying to come to grips with the structure of the cortical neuropil. (It was probably a hopeless enterprize with the methods then available.) This work became generally known in the German translation by D. Miskolczy, and the authors point out with justification that some changes had been made against the original Spanish edition, but whether they have been authorized by Cajal himself or by Tello cannot be decided now, because Miskolczy also died over 10 years ago. However, having known Miskolczy and his unlimited admiration for Cajal, I am quite certain that the German translation reflects Cajal's views as exactly as is ever possible. The reviewer might easily spend a further 10 pages in pointing out hundreds of observations, magnificent drawings, and admirable insights of Cajal, as faithfully presented by the authors of this volume. Ramrn y Cajal appears here as the unique genius in whatever he touched or whatever came into the orbit of his attention. Unfortunately, my impression is not so unequivocally favourable with respect to some of the comments made by the authors in the Preface and in the concluding Part VI, given the general title A Modern View. Although the distinguished authors claim that the book is a "joint effort" (p. XIII)--most commendable in view of having to translate from three different languages--I still cannot resist the intuition that my following criticism should be addressed to only one of the authors (E.G.J.). To demask myself as a "wicked near octagenarian" I ought to confess that my intuition is reinforced by the ancient Roman question in juridical inquiry: "cui prodest "? How should one understand the pejorative reference (p. XII) "with the exception of Lorente de Nr's understandably superficial general account of 1938",... (my italics)? I could only wish that all contemporary general accounts would be half as imaginative and the histology half as perfect as Lorente de Nr's Golgi material [see also other papers from the same year on the histological background in the early study by Lorente de N6 (J. Neurophysiol. 1, 195-206, 1938) of synaptic transmission electrophysiology]. Or how does the statement in the same paragraph "The modern period of interest in Golgi studies began in the early 1970s. . . . " relate to the fact that M. E. and A. B. Scheibel published their fundamentally new views, based on Golgi material, on the reticular formation in 1958, and several other Golgi papers already in the years 1954-1955; or C. A. Fox whose papers on the structure of the cerebellum date from 1954 to 1957, not to speak of many papers over the 1960s? These authors were working in the U.S. (and published their
569
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Book Review
papers in English) and were not from Eastern Europe, where the tradition of very good Golgi studies has been kept up in Russia without interruption. The concluding Chap. 30 brings as a most welcome gift some excellent photomicrographs of Cajal's original Golgi sections. But the account of the recent studies on the cortex is strongly lop-sided. It would be out of place and probably not exactly in "good taste" if I went into details here. Let me only mention Fig. 299, a diagram of the major non-pyramidal cell types in the primate cortex with the remark in the legend ("after Jones 1975"). It may be that my comprehension of the delicacies of English expression is insufficient, but this conveys to me the meaning that this diagram was taken from the 1975 paper. Strangely, the diagram does not exist in the copy of J. comp. Neurol. 160
(1975) that reached our library. This paper is cited all over Chap. 30 as the fundamental source of reference for newer work on the cerebral cortex. It is a very competent and superbly illustrated paper, but is somewhat lacking in vision. Ram6n y Cajal had competence, vision and imagination in the highest degree, and in spite of occasional sharp language in controverse, he always remained very modest--but, of course, he was a genius. However, such grumblings of an old participant in this lovely game should not diminish our thanks to both the authors and the editors for having undertaken and accomplished this important task. This book should be on the bookshelves of every institution and individual engaged in the study of the neurosciences. J. SZENTAGOTI-IAI
BOOK REVIEW Cajal on the Cerebral Cortex (An Annotated Translation of the Complete Writings). By J. DE FELIPE and E. G. JONES. Oxford University Press, Oxford. 654 pp. $65.00. An English translation of the works of Ramrn y Cajal has been overdue for about 25 years. The volume entitled Cajal on the Cerebral Cortex is a great treasure even for someone having lived for half a century in close, almost everyday contact with the full series of the Revista Trimestrial Micogrdfica and the Trabajos del Laboratorio de lnvestigaciones Bioldgicas de la Universidad de Madrid, and the large collections of reprints gathered by the Hungarian admirers and "friends in arms" of Cajal: M. v. Lenhossrk, Karl Schaffer and D. Miskolczy. Now we can read the complete works of Cajal on the cerebral cortex in the translation of someone who has Spanish as his mother tongue without the fear of misunderstanding or misinterpretation. The authors have to be congratulated for their decision to present Cajal's papers chronologically in (I) an early period, (II) an "interlude", based mainly on the use of Methylene Blue supravital staining, (III) the middle period, covering the bulk or the hard core of the observations, (IV) the years of consolidation, when the material became synthetized in the large comprehensive books of Ramrn y Cajal on the nervous system, and (V) works from the "final years" (1921-1935). This puts the entire development of Cajal's understanding into its proper historical perspective, and gives the volume its real fascination. It reads almost as a modern bestseller of a mystery or detective novel, where one of the greatest stories of scientific discovery unfolds before our eyes-unfortunately only for those initiated in the neurosciences-a unique story as the accomplishment of a single demigod-like individual, comparable only with the great geniuses in art; figures like Leonardo, Shakespeare, or Mozart. An equally important asset of the volume are the carefully collected annotations, separately the notes given by Cajal and the authors', editorial notes. This feature renders this book a most valuable aid for anybody interested in the true history of the neurosciences. Also of particular importance are smaller chapters (e.g. Chaps 7 and 8), giving samples from Cajal's works during the years 1892-1894, containing most significant new insights about the general morphology of the pyramidal cells, an early and today well supported circuit model of a cascading connection between successively deeper positioned pyramidal cells, and--most signific a n t l y - a n essentially correct view of cortico-cortical connections with longitudinal (ipsilateral) and transversal (callosal) pathways. The applications by Ram6n y Cajal of the Methylene Blue stain to the cerebral cortex during the years 1896-1897 are very aptly listed in the volume as "An Interlude" and their crucial significance is correctly appraised. Using this stain, Cajal could convince himself and the majority of neurohistologists of the reality of the spineous dendritic appendages. Additionally, the characteristic differences between the spines in different neuron types is described exactly as it became known much later in electron microscopy (Fig. 48). It is only to be regretted that the delicate drawings of Cajal in blue colour of the original publications could not be reproduced in colour (for obvious cost reasons), because it is in these drawings that his unmatched power of observation and draftsmanship shows up to its greatest advantage.
One might go on and on through this excellent selection of Cajal's works on the structure of the cerebral cortex, and the development of his anatomo-physiological understanding of the cerebrum. The highlights of this long process are given in Chap. 25, and it is worthwhile for the contemporary student of the brain to retrace the road of Cajal's thinking three-quarters of a century ago; if it were only to see how little the changes are in our insight into the essentials, in spite of the explosive development in practically all fields of the neurosciences. Chapter 29 summarizing the final view of Cajal as reflected in his major last treatise: ~Neuronismo o Reticularismo? (1933) is treated rather briefly. But we cannot object to this, because the large part of this work is a defence of the neuron theory against renewed attacks by a new generation of reticularists. Only relatively little on the cerebral cortex appears in this, otherwise probably the most brilliant of Cajal's writings, apart from trying to come to grips with the structure of the cortical neuropil. (It was probably a hopeless enterprize with the methods then available.) This work became generally known in the German translation by D. Miskolczy, and the authors point out with justification that some changes had been made against the original Spanish edition, but whether they have been authorized by Cajal himself or by Tello cannot be decided now, because Miskolczy also died over 10 years ago. However, having known Miskolczy and his unlimited admiration for Cajal, I am quite certain that the German translation reflects Cajal's views as exactly as is ever possible. The reviewer might easily spend a further 10 pages in pointing out hundreds of observations, magnificent drawings, and admirable insights of Cajal, as faithfully presented by the authors of this volume. Ramrn y Cajal appears here as the unique genius in whatever he touched or whatever came into the orbit of his attention. Unfortunately, my impression is not so unequivocally favourable with respect to some of the comments made by the authors in the Preface and in the concluding Part VI, given the general title A Modern View. Although the distinguished authors claim that the book is a "joint effort" (p. XIII)--most commendable in view of having to translate from three different languages--I still cannot resist the intuition that my following criticism should be addressed to only one of the authors (E.G.J.). To demask myself as a "wicked near octagenarian" I ought to confess that my intuition is reinforced by the ancient Roman question in juridical inquiry: "cui prodest "? How should one understand the pejorative reference (p. XII) "with the exception of Lorente de Nr's understandably superficial general account of 1938",... (my italics)? I could only wish that all contemporary general accounts would be half as imaginative and the histology half as perfect as Lorente de Nr's Golgi material [see also other papers from the same year on the histological background in the early study by Lorente de N6 (J. Neurophysiol. 1, 195-206, 1938) of synaptic transmission electrophysiology]. Or how does the statement in the same paragraph "The modern period of interest in Golgi studies began in the early 1970s. . . . " relate to the fact that M. E. and A. B. Scheibel published their fundamentally new views, based on Golgi material, on the reticular formation in 1958, and several other Golgi papers already in the years 1954-1955; or C. A. Fox whose papers on the structure of the cerebellum date from 1954 to 1957, not to speak of many papers over the 1960s? These authors were working in the U.S. (and published their
569
570
Book Review
papers in English) and were not from Eastern Europe, where the tradition of very good Golgi studies has been kept up in Russia without interruption. The concluding Chap. 30 brings as a most welcome gift some excellent photomicrographs of Cajal's original Golgi sections. But the account of the recent studies on the cortex is strongly lop-sided. It would be out of place and probably not exactly in "good taste" if I went into details here. Let me only mention Fig. 299, a diagram of the major non-pyramidal cell types in the primate cortex with the remark in the legend ("after Jones 1975"). It may be that my comprehension of the delicacies of English expression is insufficient, but this conveys to me the meaning that this diagram was taken from the 1975 paper. Strangely, the diagram does not exist in the copy of J. comp. Neurol. 160
(1975) that reached our library. This paper is cited all over Chap. 30 as the fundamental source of reference for newer work on the cerebral cortex. It is a very competent and superbly illustrated paper, but is somewhat lacking in vision. Ram6n y Cajal had competence, vision and imagination in the highest degree, and in spite of occasional sharp language in controverse, he always remained very modest--but, of course, he was a genius. However, such grumblings of an old participant in this lovely game should not diminish our thanks to both the authors and the editors for having undertaken and accomplished this important task. This book should be on the bookshelves of every institution and individual engaged in the study of the neurosciences. J. SZENTAGOTI-IAI