SPECIAL BOOKS.
In a study of what constitutes the foundations of zoölogy we know of no one better equipped to discuss the various problems than Professor Brooks.[V] As an original investigator in many groups of invertebrate zoölogy, as a student of animal life in temperate and tropical seas, as a special teacher of embryology and zoölogy for a quarter of a century, and, above all, as a profound student of the philosophical literature of the subject, his equipment is thorough and complete. A fair review of this work would be difficult without voluminous quotations from its pages.
The reader will find here the soundest, healthiest acceptance of the Darwinian theory of natural selection. He penetrates the mists and fogs of philosophical vagaries and follows the dictum of Tyndall, who, in presenting the essentials of a discussion, says, "Not with the vagueness belonging to the emotions, but with the definiteness belonging to the understanding" we are to study these matters. It is fact, fact, fact. The honest "I do not know" inspires the reader with a confidence that obscure points are not to be juggled with. He insists that the principles of science are physical, that a mechanical interpretation of Nature is reasonable and just. Referring to Huxley, he remarks that faith and hope are good things, no doubt, and (quoting from Huxley) "expectation is permissible when belief is not," but experience teaches that expectation or faith of a master is very apt to become belief in the mind of the student," and (again from Huxley) "Science warns us that the assertion which outstrips evidence is not only a blunder but a crime."
In the chapter of Nature and Nurture he brings many potent facts and arguments against the idea of the transmission of acquired traits. Without copious extracts it is impossible to do justice to this masterly presentation of the subject. The chapter abounds in aphorisms, as indeed do other portions of the work; and these alone, if serially collated with their contexts, would make a valuable little handbook for the student of biology. His chapter on Lamarck is equally strong, and the fallacies of Lamarckianisms have never been so clearly shown. "The contrast between what we may call the solicitude of Nature to secure the production of new beings, and the ruthlessness with which they are sacrificed after they have come into existence, is a stumbling-block to the Lamarckian, and the crowning glory of natural selection in that it solves this great enigma of Nature by showing that it is itself an adaptation and a means to an end, for the sacrifice of individuals is the means for perfecting the adjustments of living things to the world around them and for thus increasing the sum of life." "Whole books have been written on the marvelous fitness of the structure, the instincts, and the habits of the worker of the honeybee for its life of active industry—a life in which the male has no share, and from which the female is cut off by her seclusion in the depths of the hive, and by her devotion to her own peculiar duties. While the queen and the drones are well fitted for their own parts in the social organization of the hive, these duties are quite simple, and very different from the duties of the workers; and as these latter do not normally have descendants, and as they never under any circumstances have female descendants, all the workers are the descendants of queens and not of workers.
"Their wonderful and admirable fitness for their own most necessary part in the economy of the hive must, therefore, be inherited from parents who have never been exposed to those conditions to which the workers are adapted; and this adaptation can not be due to the inheritance of the effect of these conditions, nor can we believe that they are inherited from some remote time, when the workers were perfect females or when the queens were also workers; for the sterile workers of allied species differ among themselves, thus proving that they have undergone modification since they became sterile.
"Here we have a most complicated and perfect adjustment of marvelous efficacy to external conditions which are of such a character as to prove that the inheritance of the effect of these conditions has had no part in the production of the adaptation."
His views of bird migration, based on the matter of ovulation and not on food supply, are extremely interesting. He says: "As their eggs are very large and heavy, a high birth rate is incompatible with flight, and the preservation of each species imperatively demands that every egg shall be cared for with increasing solicitude; for while in other animals increased danger to eggs or young may be met and compensated by an increase in the birth rate, the birth rate of birds can not be much increased without a corresponding restriction of the power of flight. Every one knows how quickly birds may be exterminated by the destruction of their eggs or young, and the low birth rate of all birds of powerful flight is a sufficient reason for migration, for at the same time that their fitness for flight limits the birth rate, it permits them to seek nesting places beyond the reach of their enemies."
His critical estimate of Huxley is tersely presented. He says: "His evolution is not a system of philosophy, but part of the system of science. It deals with history—with the phenomenal world—and not with the question what may or may not lie behind it.
"The cultivation of natural science in this historical field and the discovery that the present order of living things, including conscious, thinking, ethical man, has followed after an older and simpler state of Nature, is not 'philosophy' but science. It involves no more belief in the teachings of any system of philosophy than does the knowledge that we are the children of our parents and the parents of our children; but it is what Huxley means by 'evolution.'"
Dr. Brooks credits Galton with employing simple terms to express new and abstruse truths, and we trust those who are continually wrestling with the dead languages to pick out new and distracting words to express their conceptions will profit by Galton's method.