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classes should be carried on so that the Government viz. those occupied by that crystalline series which, grant be earned," is a non sequitur ; at all events until the whatever may be its age, in the Alps always underlies Science and Art Department award grants for distinctively any sedimentary rock to which a date can be assigned. technical subjects under the new Technical Instruction | The principle of coloration agrees very nearly with that Act.

suggested by the International Geological Congress at We cannot help thinking that if due weight is allowed Bologna. Crimson denotes the deep-seated igneous rocks to these considerations the estimate of 155. a head will be of the more acid type, dull green the more basic ; Largely raised (unless compensation be sought by cutting two slightly different shades of red represent respectively down some of the more expensive trade classes); and as the older (and in most cases more acid) volcanics and the we suppose the endowment cannot be much increased, newer volcanics. Four colours are employed to express the number of students to be provided for must be the "crystalline schist” series : one, for the Central gneiss necessarily diminished. In fact, the whole scale on and some of the oldest mica-schists ; another, for the less which Mr. Plumbe has calculated the requirements of coarsely crystalline (and probably newer) mica-schists, the Institute may have to be somewhat revised. To together with calc-schists, chlorite-schists, &c.; a third, those who consider large numbers all-important, this may for certain crystalline schists, phyllites, and clay-slates seem deplorable, but we are convinced that the Com- of uncertain geological age ; and marbles are indicated mittee of the South London Polytechnic will prefer the by a deep blue. Palæozoic rocks (exclusive of Permian) interests of efficiency to those of temporary display. are coloured purple, the different series being distin

One other matter which we notice with some sur- guished by symbols ; pale brown denotes Permjan ; tints prise and regret is the apparent omission in the plans of blue represent the Triassic and Jurassic strata ; green to provide committee-rooms and other accommodation signifies Neocomian and Cretaceous; orange the older which can be utilized by local working men's organiza- Tertiary, flysch having a separate tint ; one shade of tions. We referred in our former article to the importance yellow is used for Miocene and Pliocene ; another for of making the Institutes real working class centres, and Diluvial and Alluvial deposits-the former a word of the reply of the Charity Commissioners to the deputation misleading origin, which ought to have long since disapfrom the London Trades Council on the subject was peared from geological nomenclature. supposed to be favourable to the provision in connection Very wisely, Dr. Noë has included in his map some. with each Institute of rooms which could be utilized on thing more than the Alps. Not only do we find the moderate payment by various working-class societies Jura, but also this region is extended far enough in the wluch now too often have to meet in public-houses. The direction of Dole to exhibit the remarkable exposure omission of any such provision in the plans for Battersea of the old crystalline floor, north of that town. is a serious blemish on the scheme, which, however, can on the right bank of the Rhine, in the neighbourhood, easily be corrected, as soon as pointed out.

of Sackingen, a considerable strip of crystalline rock is The Committee will have a great opportunity, which it shown, the end of the great Schwarzwald massif ; and 1 to be hoped they will use aright, of providing the in- north of the Eastern Alps we find the crystalline rocks habitants of South London with a technical and recreative indicated as they uprise from beneath the Miocene on the Institute, which in its close adaptation to local needs may left bank of the Danube, as, for example, near Linz, and serve as model for all such Institutes in the future. again at Pressburg. The geological colours also are

carried down the east coast of the Adriatic as far as A GEOLOGICAL MAP OF THE ALPINE CHAIN. Spalato, so that the connection of the Istrian and Dal

matian Alps with the main chain is made perfectly clear. Geologische Übersichtskarte der Alpen. Entworfen von

Unfortunately, however, Dr. Noë has not applied the same Dr. Franz Noë. Mit einem Begleitworte. (Wien : Ed.

treatment to the Apennines, though their connection with Hölzel, 1890.)

the Alpine chain cannot be of less geological importance, Goo OOD, and in some cases even elaborate, geological for he brings the colours to an abrupt end a few miles

maps exist for parts of the Alps; but one to exhibit west of Savona. the chain as a whole, without being on a scale so large as In one or two respects the above system of coloration to be unwieldy or so small as to be indistinct, has been seems open to criticism. The tint and the lines used to hitherto a desideratum. This has now been supplied by indicate mountain land are productive of some confusion, Dr. Noë. The scale adopted is 1 in 1,000,000, or about and increase the difficulty of identifying the colours, with56 miles to the inch, which very well satisfies both the out, as we think, producing a compensating advantage. above conditions. A glance at the list of authorities The use of three colours for the Trias-Rbætic seems a which have been consulted indicates that Dr. Noë has disproportionate subdivision when only one is allotted bad no easy task ; for in Alpine geology there are indeed to Neocomian-Cretaceous. We are, however, disposed consellors enough, but their multitude is not strength, for to differ more seriously—though only occasionally-from they are so often at variance.

Dr. Noë as to his use of the colours for the divisions of the At the present stage of knowledge, the chartographer crystalline schists. One of these is made too inclusive, must be content, in dealing with the crystalline schists because it is applied to clay-slates and phyllites as well as using that term in a rather wide sense), to colour his map to rocks which inust be admitted to be crystalline schists,

petrographically—that is to say, he must, as far as possible, Granted that there is sometimes a difficulty in separating record facts and avoid theories. Dr. Noë has endea- these in the field, we fail to see the propriety of delipoured, though not with complete success, to render his berately effacing the distinction. Fortunately, however, maps petrographical in the parts where doubt might arise, this confusion, owing to the scale of the map, does not

seriously mislead the student, but we are more perplexed longevity and the means of attaining it," but only to to discover the reasons which have led in some cases to show that the maxims and laws which common-seng the separation of the crystalline members of this group would dictate hold good, that the real elixir vita is to from certain of those in the other, and presumably older be found in the observance of them, and that, as a general group, which is defined as consisting of “mica-schists rule, those persons live the longest who might be expected calc-mica-schists, chlorite-schist, &c. To the latter are to do so." referred the schists-calcareous, micaceous, and chloritic The author also emphasizes the fact of the all-import-near Windisch-Matrei ; to the former the great belts ance of inherited predisposition among the factors tha: north and south of the Tauern range, which, for instance, tend towards producing longevity, and shows that nearly occur respectively near Mittersill and Lienz. We cannot all the subjects of the returns came of a long-lived stock understand on what grounds these are distinguished. In most of them, too, the body was well-proportioned Further, the great group of schists which sweeps along on and developed, brain development fair, and there was the eastern flank of the watershed of the Franco-Italian a remarkable absence of degenerative changes in the Alps, as, for example, near the Mont Genèvre, has the same arteries and cartilages. According to the author, theit colour as those of Windisch-Matrei; but petrographically essential characteristic is that all parts of the body are they appear to us inseparable from the other group. so well balanced, that the senile decay of function goes on By some geologists, as is well known, the “lustrous in them all simultaneously, and at an equal rate, so that, schists " have even been mapped (erroneously no doubt) as e.g., the vascular system is not overloaded and overaltered Trias.

worked by a too vigorous digestive apparatus, nor the Still, though we venture to dissent occasionally from vessels worn out by an over-excitable nervous and Dr. Noë, and think that in all probability a wider cardiac mechanism, so that if we could induce all our personal knowledge of the Alps would have led him organs occasionally to modify a conclusion and to avoid

"to arrange

This not to be avoided change, some slight inconsistencies, we cannot conclude this

So as to change together," notice without expressing our sense of the very great value of his work. He has placed a really good general we should have gone far towards attaining the secret of map of the Alps within the reach of all students, for the long life. price at which it is sold is surprisingly low. The map is Most of the persons described were temperate, taking accompanied by a useful descriptive pamphlet, to which little alcohol and meat, and lived active open-air lives Prof. Suess has written a short preface.

There are one or two startling exceptions to the former T. G. BONNEY. rule, however ; such as the centenarian who " drank like

a fish all his life," and several others who had always indulged pretty freely in stimulants.

Another point that Prof. Humphry lays stress on is the OLD AGE

fact that most of these people were early risers, and Old Age. By George Murray Humphry, M.D., F.R.S, processes are more complete and regular when they are

could do with little sleep. It seems that the anabolic (Cambridge: Macmillan and Bowes, 1889.)

accomplished quickly. Apropos of this, he quotes with N spite of pessimistic philosophies, man still regards approval the dictum of the Duke of Wellington: "When

age, however miserable his life may seem to impartial In discussing the general aspects of his subject, be critics. This desire, of course, is a necessary condition shows that old age may be said to be a product of of human existence, and the destruction of it would entail civilization, the law of the “weakest to the wall" being the extinction of the human race-a contingency, however, altered by the growth of sympathy, and of love for others which is never likely to arise. Hence, we have no doubt But the continued existence of old people among com that this volume will be eagerly scanned by innocent munities may (partly, at all events) be accounted for on persons who are still in hopes of finding some panacea more utilitarian principles. Weismann remarks :which will enable them to attain the desired length of

“ It (old age] is obviously of use to man, for it enables days.

the old to care for their children, and is also advantageous But, alas, the number of their somatic cell generations in enabling the older individuals to participate in humas is already fore-ordained in the germ from which they affairs, and to exercise an influence upon the advancement were developed ; and no rule of life can increase this. of intellectual powers, and thus to influence indirectly the No man by taking much thought can add a cubit to his maintenance of the race.” stature, nor a decade to the predestined span of his exist- Thus we see the production of old age could be a ence. Yet the facts gathered together in this book may counted for simply on the laws of natural selecties afford some hints as to the best way of attaining just among nations. this limit.

The fertility of these long-lived individuals is also On p. 135, et seq., Prof. Humphry reviews the chief above the normal (the average of children born to card, characteristics in the mode of life of the favoured subjects whether man or woman, being six), and many of these of the work. He begins by saying that the results of the seem to have borne or begotten children to an advanced collective investigation respecting old age, “have not age. This, again, is in accordance with the view adier been such as to evolve anything very novel or startling, cated by the biologist just quoted-viz. that a lengthening or to give rise to any fresh theories with regard to of life is connected with the increase in the duration at

reproduction. The effects of this fertility of long-lived than in the parts dealing with well-established facts and people must give their stock an advantage in the race principles. There are few general text-books which treat for existence, so that one would expect their number, in this important branch of astronomy in a satisfactory proportion to the rest of the population, gradually to manner, and it is perhaps not to be wondered at, as the increase.

constantly increasing number of new observations necesThe last chapter gives a short account of the maladies sitate considerable changes in our ideas. As far as a of old people, and is chiefly of medical interest.

consideration of the facts is concerned, however, Prof. Besides the general account of the subject, Prof. Young has done his work admirably, but this cannot be Humphry gives all the analyses of the British Medical said of his treatment of the various conclusions which Association returns, which furnish the material for the have been drawn from them. In his introduction, Prof. book. There are several good photographic illustrations: Young tells us that he has tried to treat every subject in the frontispiece, portraits of a man and his wife (both such a way as “to discourage narrow and one-sided ways over for years), and others, representing sections through of looking at things, and to awaken a desire for further the neck of the thigh-bone, and the jaw of old people. acquisition.” However he may succeed with his readers, With regard to the femur, Prof. Humphry points out it does not seem that he has altogether taken this lesson that there is no foundation for the generally accepted to heart himself, for we find him dismissing suggestions idea that the head in old people sinks to or below the level without a complete hearing. For instance, in connection of the great trochanter, and the illustration certainly bears with the theory that sun-spots are formed by the downout his criticism.

rush of cool materials into the photosphere (p. 130), he Perhaps the happiest feature of the book is its states that it is not easy to reconcile this view with the optimism. “ It is satisfactory to note how many of the distribution of the spots over the sun's surface. Further very aged are in good possession of their mental faculties enquiry on his part, however, would have shown him -taking a keen interest in passing events, forming a that the theory in its extended form suggests that the clear judgment upon passing events, and full of thoughts spot-forming material is mainly formed of vapours which for the present and future welfare of others.”

have condensed in the cool outer layers of the sun's An old age like this is worth striving to attain, although atmosphere (in the same way as water-vapour condenses one may never be free from the dread of dying “from in our own), and also gives an explanation of the way in the head downwards," and so lingering on in

which the material may be localized over the spot-zones.

The author is notably cautious with regard to new things, “Second childishness and mere oblivion, Sans teeth, sans eyes, sans taste, sans everything." but we are surprised to find that he continues to adopt

Secchi's classification of star spectra (p. 317), seeing that E. H. S.

it does not satisfactorily treat bright-line stars like y

Cassiopeia, and those of Orion which give almost conTHE ELEMENTS OF ASTRONOMY.

tinuous spectra. The classifications suggested by Vogel

and Lockyer both have the advantage of detail, and the The Elements of Astronomy. By Prof. C. A. Young, latter is certainly the most philosophical. On p. 318 it is Ph.D., LL.D. (Boston and London: Ginn and Co. stated that stars of Secchi's fourth type usually “show a 1890.)

few bright lines,” in addition to the carbon absorption T: THIS is a valuable addition to the existing text-books bands, an idea of Secchi’s which was shown to be

of astronomy for the use of those who intend to erroneous several years ago. study the subject seriously. It has much in common The book is abundantly illustrated, and most of the with the same author's larger work on “General diagrams are excellent. Fig. 119, however, gives a very Astronomy” (see NATURE, vol. xxxix. p. 386), but we are bad impression of the spectrum of a nebula, the three assured that it is not merely an abridgment, but has bright green lines being represented as almost equidistant, been worked over with special reference to a high-school whereas they practically form a triplet. A useful course. It is assumed that the students have mastered “Uranography” is given at the end. This embraces the the ordinary elementary subjects, and are acquainted with more important celestial objects in the northern hemielementary algebra and geometry.

sphere and some degrees south, and is accompanied by a The book covers quite as much ground as can be series of star maps. In the maps a convenient system of expected for an elementary course, although many of the indicating magnitudes is adopted, but it has the dissubjects are merely glanced at. Practically everything, advantage of destroying the appearances of the constellawith the exception of the more difficult problems of tions for rapid identification.

A. F. mathemnatical astronomy, is considered more or less. The opening chapters deal with definitions, the geometry of the sphere, and the determination of latitude and longi

OUR BOOK SHELF. tude. Chapters on the earth's dimensions and motions, Physiology of Bodily Exercise. By Fernand Lagrange, the moon, sun, planets, comets, stars, and nebulæ, then M.D. (London : Kegan Paul, Trench, and Co., 1889.) follow. An appendix includes topics which might be This book at first sight reminds one of the saying that a considered beyond an elementary book, but are still of German takes a year to make a research, and a week to sufficient importance to form part of a high-school write an account of it, while a Frenchman takes a year course.

to write a book on one week's work. The only original

part consists of a few experiments on the influence of Astronomical physics receives a fair share of attention, fatigue in producing increased excretion of urates in the but bere the book is necessarily more open to criticism urine. The author ascribes most of the ill effects of

fatigue to the presence of uric acid in the blood-in fact, rather than as due to the ill-treatment by over-ansions considers a fatigued man to be in exactly the same con mothers not content to let Nature alone in ber progresy dition as a gouty man. His observations, however, towards recovery: Having assumed that vaccination is seem to have been very few in number, and the analyses no protection against small-pox, the book goes on to show were all made for him by a friendly chemist. Still, it is that the only means we have of controlling the devastaunfair to the book to regard it as a contribution to the lions of this disease is by attention to sanitary arrange advance of physiological science. It is really an excel- ments and by isolation, perhaps combined with judicious lent little account of the physiology of bodily exercise, inoculation. The latter, the book assures us, is a more and its rôle in the maintenance of health, by a medical scientific procedure than the inoculation of cow-pax practitioner. It seems to be chiefly culled from the Next, the author is very angry with Jenner for calling standard French works on general physiology, and on vaccinia, “cow-pox" or "variola vaccinia." To this the physiology of movement. The author has digested stroke of dexterity by Jenner is to be attributed, say his materials well, and so produced a very readable and Prof. Crookshank, all the credit that vaccination has lucid account of his subject. For a book of its class, it is attained ; thus for a single happy thought Parliamen remarkably free from mistakes, though physiologists gave Jenner £30,000 as a consequence of his conceit, ang might not agree with him in his account of the produc-England has been made to submit to the most tyrannical tion of breathlessness or the causation of gout.

of laws. The style is simple, and the book is well adapted for This carping at the pioneer of new knowledge, ano popular use, and ought to find favour with our exercise- more especially at those forecasts of his which necessarily loving countrymen.

E. H. S. could only be verified by the lapse of time, is certainly Boilers- Marine and Land. By Thomas W. Traill, comprehend not only the immense value of vaccination.

not calculated to shake the faith of those who now falls F.E.R.N., M.Inst.C.E. Second Edition. (London: but also the small amount of mischief which it has ever Charles Griffin and Co., 1890.)

done. This volume is a second edition of a work noticed in The best that can be said for Prof. Crookshank's word these columns last year. It was then a pleasure to ex- is that it is well published. The printing is bold and press the opinion that the work would be useful to all clear, and the lithographs, such as they are, wel connected with this particular branch of mechanical reproduced. engineering. The author has found it necessary to extend

Vol. ii, contains reproductions of original papers, most the tables of scantlings, &c., from 160 to 200 pounds if not all of which are out of print, and cannot now be pressure per square inch. This in itself is sufficient obtained except at fancy prices evidence of the continued increase of steam pressures Had Prof. Crookshank been satisfied with editing these used in marine and stationary engines-probably the only and had he refrained from expressing his opinions, we practicable direction in which greater economy of fuel is to should have been grateful to him. The book does no be obtained. These increased steam pressures have also pretend to be a practical work on the subject of which it the advantage of diminishing the gross weight of machinery treats; and for the rest it might have been compiled by on board ship.

the average anti-vaccinator.

ROBERT CORY. The greater use made of mild steel by engineers generally is interesting, considering the fight the steel manufacturers had a few years ago to get it used at all in

LETTERS TO THE EDITOR. place of iron for many purposes. Mr. Traill observes that,“ notwithstanding the peculiarities of mild steel, it (The Editor does not hold himself responsible for opinions a is a material which may be used with safety and advan

pressed by his correspondents. Neither can he undertak tage, if proper precautions be taken and due consideration

to return, or to correspond with the writers of rejecte: given to these peculiarities ; possibly it has fewer in

manuscripts intended for this or any other part of NATURK

No notice is taken of anonymous communications. ] firmities than iron; and there can be no doubt that it is a better and more serviceable material for general use in The Transmission of Acquired Characters, the construction of boilers." This is the experience of

and Panmixia. most engineers intimate with the general behaviour of I SUPPOSE that a correspondent has no claim to limit the the material when being worked up into boilers and other scope of discussion in such a journal as NATURE. Aittie constructions. To the many tests and safeguards specified same time I feel it to be a rather severe burden when I am calki to prevent the use of a brittle and bad steel in any erection upon to expound, in answer to one letter after another, the mers is due the present excellence of this material, nor should conmon-places of the subject under discussion, and to retai) u they now be in any way relaxed, for to accept material, this place the substance of books like Weismann's "Esays either iron or steel, on any particular brand is a mistake.

and Wallace's “Darwinism” (to which the attention of your The general utility of the work has been increased by readers has been already drawn by reviews), not to mention the the addition of other matter and tables. The volume " Philosophie Zoologique" and the "Origin of Species." by cannot fail to be of very great use to engineers. It is seems to me that there might be interest and proht in opening nicely printed, got up in a handy size, and strongly, yet seem to tell in favour of either the Lamarckian or the antipliably bound.

N. J. L.

Lamarckian theories, or to novel criticisms of any cases whud The History and Pathology of Vaccination. Edited by citation of familiar exploded cases," and the reiteration et

have already been discussed elsewhere ; but surely the repeated Edgar M. Crookshank, M.B. Two Vols. (London : arguments and beliefs which have long since received attention H. K. Lewis, 1889.)

is not fair to the writers who have dealt

with these cases and these The arguments adopted in this work belong to a mental arguments in admirable treatises which are well known (I ami attitude identical with that displayed by anti-vaccinators happy to think) to nearly all serious students of these questions in their clamorous treatment of the subject. They are

When I saw the distinguished name of Mr. Herbert Spencer sophistical from beginning to end, and even as a book of at the end of a letter in your issue of March 6, I anticipated reference the volumes are not without drawbacks.

some real contribution to the discussion as to whether acquired Firstly, the argument is that cow-pox is to be regarded | ago expounded his convictions in favour of Lamarck in one

characters are transmitted or not. Mr. Spencer some few years as akin to syphilis rather than to small-pox, and that of the monthly reviews. His present letter is not only di therefore cow-pox is no protection against small-pox. On appointing, but is unfortunately likely to mislead the uninthis hypothesis ulcerated arms sometimes occurring after formed. Mr. Spencer states what we all know, viz. that Mt. vaccination are to be regarded as reversions to type, | Darwin considered that the effects of habit and of ase and

disuse are transmitted from the affected generation to its off. due to inherited mutilation, though he supposes they may have spring. He refers by chapter and page to the instances which become deficient through disuse. He regards the defective Mr. Darwin considered as examples of the transmission of the eyes of cave-animals as due to the inheritance of the effects of effects of habit or of use and disuse. He then says: "Clearly disuse. I can scarcely doubt that, had it occurred to him, he the first thing to be done by those who deny the inheritance of would have preferred an explanation similar to that given by acquired characters is to show that the evidence Mr. Darwin him of the wingless island beetles, viz. that a natural selection has furnished by these numerous instances is all worthless." I of animals with defective eyes takes place in a cave; since entirely disagree with this way of putting the matter. It is not ultimately only those remain in a cave and breed in it which, secessary to show that anything Mr. Darwin wrote was "worth in the course of their wanderings, are unable to see the faint less," but it is necessary to show that certain facts cited by Mr. light which penetrates to a great distance from the mouth, and Darwin admit of another interpretation or explanation than that must guide all those but the congenitally blind or weak-sighted which he gave to them. Naturally those who have taken up to the exterior. The defective eyes of moles are ascribed by the anti-Lamarckian position have done long ago what Mr. him not merely to disuse but to the selective action of inflamHerbert Spencer says is the first thing for them to do. Of mation. The case of the silkworm caterpillars with defective course the cases cited by Darwin were the first to be dealt with. instincts (which is one of those given by Nr. Spencer) does not It is extremely unfortunate that Mr. Spencer has not come appear to me to bear on the present question. Of acquired across the work in which this is done. Otherwise, instead of a characters, other than those due to disuse, Mr. Darwin accepts well-meant direction from Mr. Spencer as to what we ought to very few as being transmitted. He accepts the statements of do, we might have the advantage of reading what he has to say Brown-Séquard as to the transmission of the effects of mutilaafter considering what has been done. It is seven years since tions of guinea-pigs only so far as to "make us cautious in Prof. Weismann published his essay on heredity; last spring denying such transmission." He regards the dislocation of this and other essays appeared in English under the auspices of the eye of flat-fishes as due to the inheritance in successive the Clarendon Press. In that particular essay Darwin's cases generations of an increasing displacement caused by muscular are dealt with at length. Am I to reproduce Prof. Weismann's effort. Besides these two instances (noted by Mr. Spencer) essay or a précis of it in this letter? Will not Mr. Spencer there is one other prominent passage in which Darwin asserts his and others who are interested in these matters read Weismann's belief in the inheritance of an acquired character which is not "Essays "? I think that those who will take the trouble to do merely the result of disuse. I am anxious to separate those cases so will see that Mr. Spencer's injunction was superfluous. which Darwin speaks of as "due to the effects of disuse,"

It is, however, apart from other branches of the question, for a reason which will appear below. The additional passage important that a correct appreciation of Mr. Darwin's position not noted by Mr. Spencer is this (" Origin of Species," p. 206, in this matter of the "transmission of acquired characters" sixth edition):-"If we suppose any habitual action to become should be arrived at. Mr. Herbert Spencer's letter is, I think, inherited-and it can be shown that this does sometimes happen likely to produce an erroneous conception on this matter. We then the resemblance between what originally was a habit and know from his letters published since his death that Darwin an instinct becomes so close as not to be distinguished. If held the "Philosophie Zoologique" to be "veritable rubbish”- Mozart, instead of playing the pianoforte at three years' old with ** extremely poor; I got not a fact nor an idea from it." The wonderfully little practice, had played a tune with no practice at Dotion that his own view was a modification of Lamarck's all, he might be truly said to have done so instinctively. But it appeared to Darwin absurd. The "obvious view" was pro would be a serious error to suppose that the greater number of pounded by Lamarck, he says, " that if species were not created instincts have been acquired by habit in one generation and then separately they must have descended from other species, and I transmitted by inheritance to succeeding generations. It can can see nothing else in common between the Origin' and be clearly shown that the most wonderful instincts with which Lamarck." This was Mr. Darwin's attitude of mind to we are acquainted-namely, those of the bive bee and of many Lamarck's theory, and the cases in which he attributes importants--could not possibly have been acquired by habit." ance to the effects of use and of disuse, and to acquired habit

, The cases of the epileptic guinea-pigs, the eyes of flat-fishes, and consequently to the Lamarckian principle of the trans- and of some acquired habits, have been discussed Weismann mission of acquired characters, are clearly to be regarded as and by Wallace. I will not now allude further to those classes concessions or admissions on his part, given with increasing of cases. But I am anxious to draw attention to the special generosity in the later editions of the "Origin"; but always subject of the “effects of disuse" as set forth by Mr. Darwin. treated as of quite subordinate importance. It is not going too This phrase is not only used by him in regard to special infar to say that Mr. Darwin never troubled himself very much stances, but, in treating of the large subject of rudimentary with the question as to whether acquired characters are trans- organs, he frequently refers to the effects of disuse." He mitted or not. It was the object of his works to show that the says, "It appears probable that disuse has been the main agent main effective principle in the origin of species is the natural in rendering organs rudimentary” ("Origin," p. 401). selection in the struggle for existence of congenital characters. Now I am anxious to point out three things in regard to the He explicitly states that he believes other causes to be at work; "effects of disuse." (1) There are other possible effects of une of which at least, viz. sexual selection, he himself investi- disuse of an organ than the dwindling of that organ in one gael ar length. It must be remembered that no evolutionist generation, and the inheritance of the organ in a diminished size in Darwin's life-time had prominently challenged the truth of the by the next generation. (2) The anti-Lamarckians attribute a Lamarckian assumption that acquired characters are transmitted. very great effect to disuse, although they do not attribute to it For Darwin it was sufficient to show that, granting such a the particular result which Lamarck did. , (3) The particular process to take place, it would not account for much; he way in which, according to the anti-Lamarckians, disuse acts so was content to accept it as a subordinate factor. His view is as io lead to the dwindling or complete loss of the disused organ best stated in his own words in the "Origin of Species": has been called by Weismann by a convenient name-"panmixia." "On the whole we may conclude that habit, or use and disuse, The doctrine of panmixia is already indicated by Darwin him. have, in some cases, played a considerable part in the modi- self, and in view of this fact we must suppose that, when he fication of the constitution and structure."

attributed the loss or dwindling of an organ to "disuse” or the Whilst it is true that Mr. Darwin in various parts of his "effects of disuse," he did not necessarily (though probably he works alludes to cases which he interprets as due to the trans- frequently did) refer to the Lamarckian modus operandi of mission of characters acquired by parents through habit, use, or disuse, but may very well have had in mind the results which disuse, it is obvious, when we read what he has to say in each are a tributed to disuse by the anti-Lamarckian doctrine of case (as in the examples cited by Mr. Herbert Spencer), that panmixia. he preferred, where it occurred to him another interpretation. The doctrine of panmixia is this. When there is no longer, Thus, after referring to the wings of the logger-headed duck owing to changed conditions of life, any use for an organ, it and the domestic Aylesbury duck as dwindled by the trans will cease to be the subject of natural selection. Consequently mission in successive generations of the effects of disuse, he all possible variations of the organ will have (so far as the now interposes his own explanation by natural selection of the wing- lapsed use of the organ is concerned) an equal chance. Amongst less beetles of Madeira, prefaced by the words : " In some cases the possible variations there will be the variation in the direction We might easily put down to disuse modifications of structure of increased size, and its exact complement the variation in the which are wholly or mainly due to natural selection." He direction of diminished size. Prof. Weismann has stated briefly refuses to regard the defective anterior tarsi of dung-beetles as that this equal survival of all possible variations must lead to the

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