HEREDITY.

Otago Daily Times, Issue 14245, 20 June 1908, Page 7

HEREDITY.

By J. Arthur Thomson, M.A., Regius Prolessor ol Natural History in the University of Absrdeen. Author or "The Study of Aniuiul Life," " The .Science of Life," " Outlines ot Zooiogy," "life Progress of Science," Herbert Spenoer, etc. Joint author ot " The Evolution of Sex." i London: John Murray. Duuedin: Whiiooinbe and Tombs (Lid.). H. J. Stark ami Co. and Braithwaite's Book Arcade. 10s Gd. 'I'his is tine latest, addition to one of the best series of scientific books issuing from the press of to-day. The volume lias been long in preparation, for it is about nine years since Mr Murray mentioned it to me as "to Ik pu'blislied shortly." It is certain that delay has done no harm in this instance, for "it lias allowed the author to incorporate in his work a great deal of important matter that'has only recently come into existence. My own opinion, after careful examination, is that Professor Thomson has produced a book that will prove of solid value to his brother biologists, and to all others oajKibie of bringing intelligent interest to bear ti"on a subject with which everyone is more or less concerned. It is, admittedly, a difficult subject, however rationally approached, and despite the euy confidence with which the " man in tlie street" dogmatises over its intricacies.

As the author says in his preface: — In recent years much progress has been made in the scientific study of heredity, and, as the literature is widely scattered, and often very technical, there mav be utility in an exposition which aim's at being comprehensive and accurate without being exhaustive or nkithematical." And he goe6 on to remark that, "simple the exposition oannot be, if one ha 6 any ambition for thoroughness, but it is probably simple enough for those who have got beyond the pottering and platitudinarianVfitage, which deals in heredity with a capital II." Of the Utility ol such a work as this there need be no em-ions question, while as to the quality of thoroughness that has gone towards the malting of it, the right kind of reader will gpealc as to that.

Ab a. writer Professor Thomson is markedly lucid, persuasive., and convincing. He hao a happy knock of presenting both liis own and other men's opinions and ideas in the fairest, most impartial manner. Add to this a. finely-developed instinct for tracing the weak spot in an argument, and; absolute courtesy in the expression of dissent'. He is at home with Iris subject; is an old hand ait it, in fact. The one thing on heredity I cltieflv treasure is a paper on the subject conitnbu'ted by him to the Proceedings of lino .Royal Society of Edinburgh in the year 1889. During all the years since, the study of this great theme has been closely, followed up and summarised in such of his fascinating popular books as "The Study of Animal Life" and "The Science of Life." Now, with a vast addition of data, (the outcome of recent research and experiment throughout the world, he has produced this, magnificent volume, which will undoubtedly bring increase to his fame as a first-rate exponent of the great present-day problems of biological science.

lam not going to attempt, an elaborate account of the book. To do so would be a piece of stupidity. To nibble laboriously at euch a piece of work would be worse than stupid-r-it would be impertinent.' But I am willing to suffer the consequences, whatever 'they' bo, of declaring thait this book should be in every library and in poreession of all who make the general and individual welfare of humanity their study. The author himself Bays that the new facts placed before his readers are " of especial interest to medical practitioners, to educationiste, including clergymen, to social reformers, and to actual or prospective parents." Ample justification of that statement will be found in die pages of his book. Apart from positive human bearings, there are extensive portions which concern the farmer and stock-breeder., There are many hundreds of such within tne confines of New Zealand alone to whom this splendid epitome can be confidently recommended. As Professor Thomson says: "vVhat is important in regard lo man's heredity is even more demonstrably important in' regard to his domesticated animals and cultivated plants." That is a true word. The labours of those who have made human heredity their chief study are not to be given practical application yet awhile. The work of such men as Francis Galton and Karl Pearson is of supreme importance., but future generations will reap the benefit of it. Here a.nd there nations and • communities are putting the new ideas into practioe; requiring medical certificates, of fitne«6 as' preliminary to marriage; disallowing the marriage of consumptive persons, and so on. These are but the beginnings. Individual liberty will require to be greatly curtailed to enable that to be done which would materially alter for the better any population anywhere.

Tiie study of heredity has put out of existence the belief that disease in any form is hereditarily tansmksable. It is now universally admitted by students of heredity that what, unfortunately, most of us do inherit, are physical qualities that are more or less ill adapted to repel the- attacks of disease when they occur. There are many dissentiente from this view, but not among the informed. Here the temptation to plunge into a dissertation on Weismannism i 3 great, but.the subject had beet be Mowed up in Professor Thomson's pages. The facts being obvious, everyone admite that many children are born already thrall to disease. Many, long before they are born, are in like sad case; but the explanation of this is now clear, and it is not heredity. In this and in other coimec-tions much'of the common confusion of thought and statement arises from faulty definition, and wnosoever reads with care Professor Thomson's opening chapter, entitled '•' Heredity and inheritance: Defined and Illustrated," will. have little excuse for any further blundering in that direction. "Heredity," _he say 6, "is no entity, no force, no principle," but a convenient term for the genetic relation between successive generations, and inheritance includes all that tJie organism is or lias to start with in virtue of its hereditary relation." A brother biologist is approvingly quoted as affirming that to speak of the "Principle of Heredity" in organisms is like speaking of tho " Principle of Horologity in clocks."

Three kinds of conclusions—those reached by microscopic study of the germeel Is, (hose reached by the'application of statistical methods, • and tl>ose reached through experiment—have been given much prominence in the book. The Mutation Theory of De Vrics is elucidated with perfect clearness, and its present limitations defined. Mendel's discoveries, ;;jid all that lins come of them since their rediscovery, arc beautifully described, ,very excellent coloured plates, diagrams, 'and figures being used to good purpose in this and other sections of the buok. Weismaiin receives masterly exposition :—Frofesor Thomson says he has been at no pains to conceal his general adherence to what is called Weismaiinism, or to take a particular case, his conviction tliat, "we do not know of any instance of the transmission of an acquired character." One of the most striking chapters is tliat on "Heredity and Development." In it is summariKed what i 6 and what is not kuown of individual development, the conclusion reached certainly tending to beget humility of mind. In such a book as this —brilliant and fascinating throughout—itis useless to lay stress on one part more than, on another. It is a great exposition of a great subject. The style in which it has been turned out merits special eulogy—"Heredity" is a worthy product of llio publishing enterprise of the house of Murray—first-rate in every particular.— DINORNIS.