The Firmament of Time by Loren Eiseley (review)

ganism. A tri-dimensional matrix ofthis sort built around the unique apposition offibers at each vacuole locus serves the author as his neural memory substrate. Furthermore: "such a memory organ . . . does not only register the signals; it integrates them as well." In the author's schema thepowerfulattributes ofthis vacuolar systemrestin the uniqueness ofthe fiber aggregation at each ofthese vacuolar nodal points. A spatio-temporal activity sequence in some or all ofthe group will permanently change the bioelectric characteristics ofa particular vacuole. Thus conditioned, future activity in but a fraction ofdie conductive elements originally involved may serve to set offthe entire spatio-temporal sequence. Professor Bok feels that such a model successfully fulfills the requirements of "associative memory," "learning," and "conditioning": "In the vacuole hypothesis the interfibralsynapsesarecalled conditionedsynapsesbecausetheirconductivity, aswasdescribed, depends on conditions prevalent in the past. They seem to be responsible for the conditioned reflexes described by Pavlov." Ifthese vacuole complexes are indeed the repositors ofmemory "bits," they must exist in sufficient numbers to provide fresh memory loci throughout life, since presumably new vacuoles cannot be generated following early development. Reasoning from the maximum number ofnerve impulses which can be produced in a lifetime by the usual complement of sense organs, io10 bits are estimated as entering the cortex. The total number ofcortical neurons (3.3 X io10) are believed inadequate numerically as a reservoir ofmemory loci, whereas an estimated 5 X 10" vacuoles should prove more than sufficient ; "and unlike the neuron cycles, all these vacuoles can be used for storage, as none of them is involved in the daily neuronal function ofthe cortex, and as each vacuole itself is a complete unit in the storage system." The author is careful to point out the hypothetical nature ofthese assumptions. They are advanced as educated guesses growing out ofa quantitative approach to histological data—as straw men for the physiologist and chemist to demolish ifthey can. It is possible to raise questions about his data-gathering methods and to take issue with his conclusions. It is more difficult to deny the power ofdie quantitative approach and the necessity ofits application to biological science. In this regard, even ifin no odier, Professor Bok's monograph contributes importantly to the literature. And though one may accept or reject some ofthe more audacious conclusions as one will, the detailed analysis ofquantitative cortical relations should provide a mine ofdata for cortical histologists— and histonomists—for years to come. Madge E. Schetbel Arnold B. Scheibel University ofCalifornia Medical Center Los Angeles 24, California The Firmament of Time. By Loren Eiseley. New York: Atheneum, i960. Pp. vii+181. $3.50. Loren Eiseley, scientist, is also a poet with a philosophical leaning which is evident in his writings. The result is that his books, lectures, and other efforts command attention 488 Book Reviews Perspectives in Biology and Medicine · Summer if61 because they give the reader or his audience a rewarding experience as he enjoys peering with the audior into die less known approach to our existence. This is especially true of his most recent book. Those ofus who enjoyed The ImmenseJourney (1957) recall thathe portrayed in somber tones man's long climb from lowly origins to his present plight in the cosmos. In The Firmament of Time the author strives to show the naturalness ofthe universe through the progression ofscientific studies. He centers his thesis on man. The book comprises six lectures given before the Department of Physiology of the College of Medicine of the University of Cincinnati under a grant from the John and Mary Markle Foundation ofNew York in 1959. These unique homilies consider the naturalness ofthe world, deadi, life, man, the humanness ofman, and "natural" itself. In the first lecture it is made clear that man is at heart bodi pragmatist and mystic. The history ofhis dualism is fascinatingly dealt with. It is suggested diat man will always carry with him this dual approach to nature. After his analysis ofman versus die machine, the author says, "Man, too, was to become as natural as the wandering stars that lighted his unknown course. He was to learn diat his habitation was unfixed. Not only he, but his tightly governed universe, was soon to be adrift and...