cates the existence in the observations of a systematic error depending upon the amount by which the measured distance differs from 120°. Reasons for supposing the error to be of subjective origin were indicated.

A discussion of the data thus corrected furnishes as the value of the constant of aberration 20" 445±0′′010

As subsidiary results of this investigation it appears that the variation in the amount of the refraction from winter to summer is better represented by Regnault's value of the co-efficient of expansion of air, o'003670, than by the values adopted in the tables of Bessel and the Pulkowa Observatory. Also, the obser vations are in very close agreement with the absolute values of the Pulkowa refractions, but indicate sensible corrections to Bessel's tables.

Section B (Physics) was prolific of good scientific work. The stereopticon views, with which vice-president Nichols illustrated his annual address, were a revelation of the astounding resources of photography in depicting phenomena of infinitesimal time, the alternating electric current with light and dark intervals clearly depicted, the flight of a bullet and its attendant sound waves shown as if at rest. Prof. Nichols does not think that he has yet reached the limit of these investigations. Although some of the exposures could only have been for a few millionths of a second, they were always long enough to secure a negative. Of equal, if not superior, merit was the delicate and accurate apparatus for measuring expansions, exhibited by Profs. E. W. Morley and Wm. A. Rogers, called the Morley interferential comparator. In a paper read before the section, Prof. Morley explained that he had first described the proposed apparatus before a meeting of the Civil Engineers' Club of Cleveland, and afterwards at the Toronto meeting of this association in 1889. I It was first used in a simplified form, in an experiment on the magnetic field, by Profs. Morley and Eddy, which was reported to the association at the Indianapolis meeting in 1890. The present paper was designed to recall to mind the principle of the apparatus and method, as an introduction to a paper by Prof. Rogers, in which several series of experiments with it were detailed, and also as a preparation for an exhibition of one of two forms of the apparatus which have been constructed for use in measuring expansions. These have been constructed by Prof. Rogers, with the aid of a small grant from the research fund of this association. It will measure the expansion of a metallic bar five or ten times as accurately as by old methods, being only limited by the accuracy with which temperature can be measured. It consists of two metallic bars, one of steel and one of bronze, with mirrors at each end, so adjusted that any change in adjustment is indicated by interference fringes of sodium light; 90,000 such fringes to the inch may be readily distinguished and counted. The mirrors are probably the most delicate ever made, being plain within two millionths of an inch, thus far exceeding in accuracy the best objectives of the largest telescopes.

Prof. Rogers followed with a paper in which he said that preliminary to the actual use of the interferential comparator in physical measurements, it was necessary to establish three points with great certainty.

(1) Does the value of the relative change per degree in the length of steel and bronze bars of metal, expressed in terms of wave lengths, remain constant? (2) Does the relative length of the two bars compared remain constant at the same temperature after the mirrors have been subjected to extreme temperatures? (3) Does this relative remain constant after the positions of the mirrors have been changed by means of the adjusting Screws provided?

As a result of many experiments, an affirmative answer can be given to the two first inquiries. The change for each degree Centigrade was proved to be 38.31 fringes of sodium light for the steel bar, and 64 23 fringes for the bronze bar of Bailey's metal. When the observed differences in length were reduced to 51, the point at which the two bars had nearly the same length, it was found that the average probable error in a single comparison was about 0.72 of a single wave length, including all observations at wide ranges of temperature.

The answer to the third inquiry was less satisfactory, as occasional changes of ten fringes were obtained. The source of this error has, however, been found. In the new vacuo apparafus, the mirrors have been matched with great exactness. It was then found that the previous matching had been defective. Prof. Morley has computed the maximum effect of this error in chang ing the apparent relative lengths of the two bars, and has found it to be fifteen fringes.

The following are a few of the problems to the solution of which the apparatus has been applied :

(1) The determination of the effect of slow changes in temperature upon the relative lengths of the two bars compared. (2) The cooling effect of evaporation from a body of water placed near one of the bars.

(3) Measurement of slow changes in the bars compared due to the near presence of the observer.

(4) Measurement of the effect of obscure rays of heat stored in large masses of matter in close proximity.

(5) Measurement of the effect of flexure in changing the length of one of the bars.

(6) Measurement of changes in length produced by placing one of the bars in a magnetic field.

(7) Measurement of the heating effect of a current passed through one of the bars.

(8) Determination of the time required for the complete dissipation of a given amount of heat quickly applied to the bars.

(9) Proof that air is practically a non-conductor of heat. (10) Determination of the value of 100 mikrons in terms of wave lengths of sodium and mercury fringes.

Prof. Alexander Macfarlane read a paper on the addition or composition of physical quantities, treating of one uniform method of the addition or composition of scalar quantities at different points, of vector quantities at the same point, of vector quantities at different points, of finite rotations round intersecting axes, of finite rotations round non-intersecting axes, and finally of screw motions. The screw motions compounded are not infinitesimal, but may be of any magnitude.

Profs. Macfarlane and G. W. Pierce contributed a paper on the electric strength of solid, liquid, and gaseous dielectrics, in which it was maintained that for a stratum of air or other gas between two parallel metal plates the electrostatic gradient when the spark passes is less the greater the distance between the plates; but for paraffined or beeswaxed paper this gradient is constant; it is also constant for paraffin oil or kerosene. The anomalous behaviour of the gaseous dielectric appears to be due to the greater freedom of motion of the molecules.

Mr. Joseph O. Thompson 1ead a paper on "Fatigue in the Elasticity of Stretching." He remarked that attention was first called to the phenomena of elastic fatigue by Lord Kelvin some twenty-eight years ago. He used the elasticity of torsion in his experiments, and demonstrated that in some cases fatigue diminished the slide modulus as much as 6 per cent. Prof. Thompson's paper called attention to the fact hitherto undiscovered that a similar fatigue can be observed in the elasticity of stretching. Its influence in diminishing the Young's modulus amounted in these experiments to less than of I per cent. The wires used were 23m. long, and the metals in which the phenomenon was observed were silver, steel, and brass.

Messrs. F. Bedell, K. B. Miller, and W. F. Wagner contributed an elaborate mathematical paper on "Irregularities in Alternate Current Curves."

At the meeting of Section C (Chemistry) the notable feature was the presentation of Prof. Morley's final determination of the atomic weight of oxygen, giving results obtained by four distinct methods of investigation and with a degree of accuracy that will render this a final determination of this weight, correct to the third decimal figure. Three years ago Prof. Morley submitted a preliminary report, in which an account was given of the determination of the ratio of densities of oxygen and hydrogen as 15.884, correct within one part in four thousand. It has since been found that an accident happened to the apparatus during the last experiment of the series, which ought therefore to have been rejected. If this were now to be done, the value would become 15 882.

Two years ago some account was given of a series of determinations of the quantities of water produced from weighed quantities of oxygen and of hydrogen. Twelve experiments were made. In one the quantity of water produced was not determined, owing to accident. From the weights of hydrogen and oxygen consumed, the atomic weight of oxygen was found to be 15 8794, with a mean error of one part in 16,0co for a single experiment. From the quantities of hydrogen used and of water produced, the value obtained was 15 8792, with a mean error of one part in 7500 for a single determination.

At the present meeting, Prof. Morley reported the result of twenty determinations of the absolute density of oxygen, and twenty of that of hydrogen. The ratio of these densities found was 15.882.

as the result so far of Prof. Morley's work.

(b)

But the later work of Scott has attained a high degree of excellence, and gives a value of the ratio of the volumes in which the gases combine, which is considerably higher than that used in this computation. Prof. Morley explained that he had himself published every experiment which he had ever made on this point, and that they had a mean error of only one part in 26,000. Since no source of constant error had yet been pointed out, he had great confidence in the accuracy of his own experiments. He, however, intended to make another series of determinations with the apparatus used before, and one with a new apparatus now constructing.

He also mentioned three other series of determinations which he is now carrying on; two are determinations of the absolute density of hydrogen, and one a determination of that of oxygen; in these a very small mean error is attainable.

were one on

Among the other papers which attracted special attention, "The Constitution of Paraldehyde and Metaldehyde," by W. R. Orndorff and John White; and one on Slability of Lead Oxide in the normal tartrates and other normal organic salts, with observations on the rotary power of the solutions thus obtained," by L. Kahlenberg and H. W. Hillyer.

In Section D (Mechanical Science and Engineering) the number of papers was small, owing to the increasing tendency of engineers to support special technical associations.

Messrs. Wm. S. Rogers, S. W. Robinson, and J. Burkitt Webb contributed useful notes on different topics; while the secretary of the section, Prof. D. S. Jacobus, read three papers describing ingenious apparatus devised and used by him at the Stevens Institute of Technology at Hoboken, N.J.

Among the papers read, we note one by Prof. J. J. Stevenson on the use of the term Catskill," in which he offered strong objection to the application of this term to the whole series of rocks from the Hamilton to the lower carboniferous, as has been recently advocated. Since the group is well defined below, and since the geographical term Catskill represents conditions which prevailed over an extended area only during the latter part of the upper Devonian period, Prof. Stevenson thinks that the term should be restricted as defined by Vonuxem.

Mr. J. A. Holmes gave an interesting description of a map and section of the stratified rocks of the coastal plain of southern North Carolina. Mr. William Hallock reported the results of further observations of temperature in the deep well at Wheeling, W. Va. Since 1891 this well has filled with water by leaking below the surface. Temperature determinations have been made in the water, which are practically identical with the determinations made when the well was filled with air two years ago, showing that there is not an appreciable circulation of water in a hole five inches in diameter. Down to 3200 feet the gradient is 1° F. to 815 feet, and near the bottom. to each 6c feet.

Dr. C. R. Van Hise, referring to the "character of the folds in Marquette iron district," called attention to the fact that what has been considered a synclinal is really a great synclinorium, having a nearly east-west axis, and having both the north and the south limbs pushed under, producing a complex fold with overturned minor folds, and comparable to some of those which Heim has described from the Alps.

Prof. C. D. Walcott exhibited beautiful specimens of trilobites which he had collected from the Utica shale of New York, on which the antennæ and legs were remarkably well preserved. Mr. F. P. Gulliver exhibited beautiful papier maché models, one of the sand plain at Newtonville, Mass., and a second showing the theoretical conditions at the time of its formation.

A paper entitled "Additional Facts Bearing on the Unity of the Glacial Period," was read by Prof. G. F. Wright, consecutively with one by Frank Leverett on “Changes of Dramage in the Rock River Basin in Illinois." The latter is important as

affording means of estimating the amount of erosion in inte glacial compared with that of post-glacial time. The wi pre-glacial channel of the Rock is followed to the Green Riv Basin near Inlet Swamp, when it is choked up by accumulation of drift. The change to the present course is located early the glacial period, since the present valley can be shown to ba been opened to about its present size and depth prior to th formation of the kettle moraine of the Green Bay lobe, the grave which occupy the new course of the river being derived from t ice-sheet at the time the moraine was forming near the hea waters of the river. These gravels are traceable up to the bexi the moraine as a moraine-headed terrace. It is found that th post-glacial erosion in the river valley is only one-half the accomplished in inter-glacial time, and whereas the post-glac erosion is mainly in gravel and sand, the inter-glacial erosio was mainly in rock strata. This seems to Mr. Leveret warrant the use of the term epoch rather than episode characterise these time relations.

Mr. Warren Upham, in his paper on "Tertiary and Quarter nary Stream Erosion in North America," argued from stream erosion that an epeirogenic uplift preceded and probably r duced the glacial epoch.

Section F (Zoology) having been severed from botany by th new amendment to the constitution, had comparatively fe papers. The president, Prof. H. F. Osborn, carried on the line of thought contained in his annual address, by a paper "The Mammals of the Upper Cretaceous," in which he pr posed a system of classification and evolution materially de ing from that of Prof. Marsh, which has so long held its great Prof. Osborn's studies lead him to more confidence in the belie that early forms are in many cases pretty highly specialised, an that evolution by degradation plays a pretty important part biological investigation. This is quite in harmony with the statement of the president-elect of the association, Dr. Brin in his public address on "The Earliest Men," above note the effect that the evolution of man appears to have been saltum.

Section G (Botany) was organised at this meeting by divis of the old section of biology, and considered a large number papers of technical interest. Among the contributors wer Arthur, Beal, Galloway, Dr. and Mrs. Britton, Barnes, Ha stead, MacMillan, Coville. Dr. Britton discussed the questic of nomenclature.

Probably the proceedings of the Botanical Club were eve more interesting to botanists than those of the section, inasm as the club organised the Botanical Society of America w twenty five charter members. Dr. Arthur exhibited to club two very interesting pieces of apparatus, one a rota machine in which a germinating seed may be placed and subjected for hours or days to centrifugal force instead of grav tion. This apparatus gives the interesting result that the ro grow in the direction of the centrifugal force, and the leave opposed to it. The other apparatus, called an auxanometer shows by ingenious automatic action the rate of growth plants.

Section H (Anthropology) furnished the largest number of papers. The first paper read in the section, by Washington Matthews, on Songs of Sequence of the Navajos," was a trated by reproductions of the songs by the phonograph. D Joseph Jastrow gave an account of the system of psycholog investigation now pursued at the World's Fair. The rece discoveries resulting from excavations at the ancient argalle quarries on Geddes' Run, near the Delaware River, were sented by II. C. Mercer; and Ernest Volk made some of vations in regard to the use of argillite by prehistoric people as illustrated by explorations in the Delaware Valley. H Rust read several papers on California Indians and imple ments. Prof. G. F. Wright presented a summary of the evidence in favour of the existence of glacial man in America which commanded general attention because of the pers abuse to which Prof. Wright has recently been subjected. T subject was discussed at some length, and Prof. Wright's c clusions were violently attacked by Mr. McGee. Dr. Brist read a paper on the "Mexican Calendar System," which pronounces an anomaly, having no relation to the period ehe of solar or lunar revolution. It consists of 20 x 13, or days. The 20 is a double digital basis. The 13 seemsi explicable.

The excursion of this section on Monday afternoon gave opportunity to visit a group of effigy mounds just across La

Mendota, about four miles from the University. These mounds are of different shapes, that of the panther predominating, though birds and conical mounds are found also.

Section I (Economic Science and Statistics) had but few papers to consider, of which that of Mr. Henry Farquhar, on "Relations of Production and Price of Silver and Gold," introduced the topic of most general interest just now. The fallacy of attempting to maintain a silver standard of value was very apparent from the paper and the ensuing discussion. provements in metallurgy reduce the cost and vastly increase the production of silver, while that of gold remains almost stationary, there being really hardly any metallurgy of gold. WM. H. HALE.

BRITISH ASSOCIATION.

Im

NOTTINGHAM, SEPTEMBER 13. THE meeting of the Association, which commences to-day, will take place mainly in the University College. In this building all the Sections, with the exception of the geographical, economical, and anthropological, will assemble. The Sections representing the experimental sciences will be accommodated in lecture theatres built and furnished for the express purpose of illustrating and demonstrating these sciences. Every convenience will therefore be afforded in the meeting rooms for the proper illustration of the papers which will be communicated. Further, the students' laboratories, which are in immediate connection with these theatres, will furnish most convenient exhibition rooms for the illustrative apparatus, specimens, and diagrams during the week of meeting, and when they are not required for illustration in the sectional room. The College will thus become the scientific headquarters during the meeting. It will in addition furnish convenient sectional committee rooms, sectional secretaries' rooms, anthropometric laboratory, ladies' boudoir, smoking-room, convenient retiring rooms, and a large luncheon buffet in the attached public lending library.

It is interesting to compare the facilities now offered for the meeting with those afforded during the preceding meeting in 1866. A temporary exhibition building then stood on the College site, and was used for the conversacione, but no suitable meeting rooms existed in the town for housing Sections A, B, C, D, and G. It will scarcely be necessary to inform those interested in the advancement of science that the existence of the College is due to the public spirit of the inhabitants of Nottingham, who willingly voted public money to establish the College, and who now mainly support it from the local rates. That such a bold experiment has met with the full success which it deserved, members of the Association who visit the town will learn and see for themselves. They will find that the initial success is leading to further success, and that outside support from the Government, from the Drapers Company, and from other sources, is now being accorded with an ungrudging hand. It may be said with truth that since the Association last met in Nottingham, the town has become in a very important sense a centre for the advancement of science, and fully deserves all the encouragement and impetus which will be given to its comparatively new scientific work and aims by the visit of the Association.

It may be added that the Sections which meet outside the College are also accommodated in halls which were non-existent at the previous meeting in Nottingham, and that the evening meetings will take place in a large hall, which is new in the same sense. This will give some idea of the rapid progress which the town has made during the last quarter of a century.

Coming, as the Nottingham meeting does, between meetings at the venerable University towns of Edinburgh and Oxford, the status of the University College of the own must necessarily suffer by comparison. But it will

be found that Nottingham, like the other provincial towns which have recently founded colleges in their midst, is by no means altogether at a disadvantage as regards its higher education by making a late start. In the matter of buildings and equipments it has benefited by the experi ence of its predecessors; and the absence of the fetters of an ancient régime has left it free to adapt its curriculum and methods to the needs of the present day.

With respect to the prospective work of the meeting, it may be stated that it promises to be fully up to the average in importance and in interest. A general statement of the papers to be brought forward, and of the discussions in the different Sections, has appeared in NATURE from time to time, and it is unnecessary to repeat the ar nouncement of these in detail. It will be sufficient to remind members that in Section A questions of great interest and importance are put down for discussion; that in Section B, M. Moissan will d monstrate the preparation and properties of fluorine, a demonstration of absolutely unique interest, since this is the first opportunity afforded in this country of seeing these remarkable experiments. The President of the Section C and his colleagues have been most energetic in securing the attendance of distinguished foreign geologists, and in procuring numerous papers of local geological interest, in addition to discussions on points of general importance. In Section D, which will have the advantage of securing the special interest and support of the President of the Association, there will undoubtedly be good discussion of important biological problems, not only by Englishmen, but also by eminent continental biologists, who are guests of the town. In Section E the travellers are mustering in force, and will have their tales to tell of widely distant parts of the earth's surface; the photographs and paintings prepared in Antarctic regions will be of special interest in this section. Economic problems of the day are to be discussed in Section F. Section G will be represented by many eminent engineers, both English and foreign, and the experimental illustration of many of the papers, rendered possible by the meeting being held in a well-equipped engineering theatre, will add interest to the proceedings. In Section H the paper by Dr. Hans Hildebrand. and : e description of the Glastonbury mars Mr. Bulleid, with the 1s cussions which they will undoubtedly give rise to, would, if they stood alone, constitute a tempting programme to anthropologists.

The efforts put forth in the town itself to make the gathering pleasant and successful will perhaps be best appreciated by reference to the local programme and maps now being issued to members. The townsmen have vindicated their character for hospitality by privately entertaining in their homes nearly 400 of their visitors. An ample list of hotels and lodgings, with a suitable map, has been issued for some weeks, some of the hotels binding themselves to a special tariff to members who engage their rooms through the local committee. The garden parties, excursions, and entertainments will be seen to have been so arranged as to leave no irksome leisure to be filled in by those who have done their duty to their Sections; and the scheme for privately engaging the Theatre Royal for the last Wednesday night will, it is hoped, justify by its success its boldness and originality.

With a programme of work of varied special and general interest and importance; with a universal desire on the part of the townsmen to do everything in their power to secure the comfort of their guests, and to afford pleasure and recreation to them; with the social element of the scientific gathering secured by the promise of attendance of men of science from all parts of our own country and from abroad; and, above all, with the promise of fine autumnal weather in a healthy, picturesque, and accessible town with most interesting surroundings,

WE are assembled this evening as representatives of the sciences-men and women who seek to advance knowledge by scientific methods. The common ground on which we stand is that of belief in the paramount value of the end for which we are striving, of its inherent power to make men wiser, happier, and better; and our common purpose is to strengthen and encourage one another in our efforts for its attainment. We have come to learn what progress has been made in departments of knowledge which lie outside of our own special scientific interests and occupations, to widen our views, and to correct whatever misconceptions may have arisen from the necessity which limits each of us to his own field of study; and, above all, we are here for the purpose of bringing our divided energies into effectual and combined action.

Probably few of the members of the Association are fully aware of the influence which it has exercised during the last half-century and more in furthering the scientific development of this country. Wide as is the range of its activity, there has been no great question in the field of scientific inquiry which it has failed to discuss; no important line of investigation which it has not promoted; no great discovery which it has not welcomed. After more than sixty years of existence it still finds itself in the energy of middle life, looking back with satisfaction to what it has accomplished in its youth, and forward to an even more efficient future. One of the first of the national associations which exist in different countries for the advancement of science, its influence has been more felt than that of its successors because it is more wanted. The wealthiest country in the world, which has profited more-vastly more-by science than any other, England stands alone in the discredit of refusing the necessary expenditure for its development, and cares not that other nations should reap the harvest for which her own sons have laboured.

It is surely our duty not to rest satisfied with the reflection that England in the past has accomplished so much, but rather to unite and agitate in the confidence of eventual success. It is not the fault of governments, but of the nation, that the claims of science are not recognised. We have against us an overwhelming majority of the community, not merely of the ignorant, but of those who regard themselves as educated, who value science only in so far as it can be turned into money; for we are still in great measure-in greater measure than any other-a nation of shopkeepers. Let us who are of the minority-the remnant who believe that truth is in itself of supreme value, and the knowledge of it of supreme utility-do all that we can to bring public opinion to our side, so that the century which has given Young, Faraday, Lyell, Darwin, Maxwell, and Thomson to England, may before it closes see us prepared to take our part with other countries in combined action for the full development of natural knowledge.

Last year the necessity of an imperial observatory for physical science was, as no doubt many are aware, the subject of a dis-, cussion in Section A, which derived its interest from the number of leading physicists who took part in it, and especially from the presence and active participation of the distinguished man who is at the head of the National Physical Laboratory at Berlin, The equally pressing necessity for a central institution for - chemistry, on a scale commensurate with the practical importance of that science, has been insisted upon in this Association and elsewhere by distinguished chemists. As regards biology I shall have a word to say in the same direction this evening. Of these three requirements it may be that the first is the most pressing. If so, let us all, whatever branch of science we represent, unite our efforts to realise it, in the assurance that if once the claim of science to liberal public support is admitted, the rest will follow.

In selecting a subject on which to address you this evening, I have followed the example of my predecessors in limiting my self to matters more or less connected with my own scientific

occupations, believing that in discussing what most interes myself I should have the best chance of interesting yuz. circumstance that at the last meeting of the Brush Ascia:. in this town, Section D assumed for the first time the which it has since held, that of the Section of Biology, C gested to me that I might take the word "biology starting-point, giving you some account of its origin and use, and of the relations which subsist between biology & other branches of natural science.

Origin and Meaning of the Term "Biology."

The word "biology," which is now so familiar as comprazg the sum of the knowledge which has as yet been acquir. 1 cerning living nature, was unknown until after the beginning the present century. The term was first employed by Trev - ants, who proposed to himself as a life-task the development of a science, the aim of which should be to study the fums 2 phenomena of life, its origin and the conditions and law of existence, and embodied what was known on these subjects 2 a book of seven volumes, which he entitled "Biology, or the Philosophy of Living Nature." For its construction 2 material was very scanty, and was chiefly derived from it anatomists and physiologists. For botanists were entirely d pied in completing the work which Linnæus had begun, a scope of zoology was in like manner limited to the descrip and classification of animals. It was a new thing to regard it: study of living nature as a science by itself, worthy to occupy place by the side of natural philosophy, and it was there, re necessary to vindicate its claim to such a position. Trevirars declined to fund this claim on its useful applications to the a of agriculture and medicine, considering that to regard any saject of study in relation to our bodily wants-in other words utility was to narrow it, but dwelt rather on its value i discipline and on its surpassing interest. He commends birlar to his readers as a study which, above all others, **nourishes 2. maintains the taste for simplicity and nobleness; which affe to the intellect ever new material for reflection, and to imagination an inexhaustible source of attractive images

Being himself a mathematician as well as a naturalist, de approaches the subject both from the side of natural philcare and from that of natural history, and desires to found the tr science on the fundamental distinction between living and e living material. In discussing this distinction, he takes as 2 point of departure the constancy with which the activities wak manifest themselves in the universe are balanced, emphasiz the impossibility of excluding from that balance the viia acur ties of plants and animals. The difference between vital us physical processes he accordingly finds, not in the nature of processes themselves, but in their co-ordination; that 5, their adaptedness to a given purpose, and to the pec.. and special relation in which the organism stands to external world. All of this is expressed in a proposins difficult to translate into English, in which he defines life as cre sisting in the reaction of the organism to external ir fleetz and contrasts the uniformity of vital reactions with the variet of their exciting causes.

The purpose which I have in view in taking you back as ! have done to the beginning of the century, is not merely commemorate the work done by the wonderfully acute writer : whom we owe the first scientific conception of the sciera of life as a whole, but to show that this concerta as expressed in the definition I have given you as its foundat can still be accepted as true. It suggests the ad of organi.m as that to which all other biological ideas must relate. It a suggests, although perhaps it does not express it, that aefiom not an attribute of the organism but of its essence-that if, un de other hand, protoplasm is the basis of life, life is the basis protoplasm. Their relations to each other are reciprocal. We think of the visible structure only in connection with the in visible process. The definition is also of value as in ficating at once the two lines of inquiry into which the science has divitou by the natural evolution of knowledge. These two lines mar be easily educed from the general principle from which Trevr anus started, according to which it is the fundamental char teristic of the organism that all that goes on in it is to the advantage of the whole. I need scarcely say that this fan-damental conception of organism has at all times presented itse

1 "Leben besteht in der Gleichfärmigkeit der Reaktenen is ungleiche förmigen Einwirkungen der Aussenwelt."-Treviranus, /** * sophie der felonien Natur, Göttingen, 1802, vol. 1. p. 8v

to the minds of those who have sought to understand the dis tinction between living and non-living. Without going back to the true father and founder of biology, Aristotle, we may recall with interest the language employed in relation to it by the physiologists of three hundred years ago. It was at that time expressed by the term consensus partium-which was defined as the concurrence of parts in action, of such a nature that each does quod suum est, all combining to bring about one effect "as if they had been in secret council," but at the same time constanti quadam naturæ lege.1 Prof. Huxley has made familiar to us how a century later Descartes imagined to himself a mechanism to carry out this consensus, based on such scanty knowledge as was then available of the structure of the nervous system. The discoveries of the early part of the present cen tury relating to reflex action and the functions of sensory and motor nerves, served to realise in a wonderful way his anticipations as to the channels of influence, afferent and efferent, by which the consensus is maintained; and in recent times (as we hope to learn from Prof. Horsley's lecture on the physiology of the nervous system) these channels have been investigated with extraordinary minuteness and success.

Whether with the old writers we speak about consensus, with Treviranus about adaptation, or are content to take organism as our point of departure, it means that, regarding a plant or an animal as an organism, we concern ourselves primarily with its activities, or, to use the word which best expresses it, its energies. Now the first thing that strikes us in beginning to think about the activities of an organism is that they are naturally distinguishable into two kinds, according as we consider the action of the whole organism in its relation to the external world or to other organisms, or the action of the parts or organs in their relation to each other. The distinction to which we are thus led between the internal and external relations of plants and animals has of course always existed, but has only lately come into such prominence that it divides biologists more or less completely into two camps-on the one hand those who make it their aim to investigate the actions of the organism and its parts by the accepted methods of physics and chemistry, carrying this investigation as far as the conditions under which each process manifests itself will permit; on the other, those who interest themselves rather in considering the place which each organism occupies, and the part which it plays in the economy of nature. It is apparent that the two lines of inquiry, although they equally relate to what the organism does, rather than to what it is, and therefore both have equal right to be included in the one great science of life, or biology, yet lead in directions which are Scarcely even parallel. So marked, indeed, is the distinction, that Prof. Haeckel some twenty years ago proposed to separate the study of organisms with reference to their place in nature under the designation of "cecology," defining it as comprising "the relations of the animal to its organic as well as to its inorganic environment, particularly its friendly or hostile relations to those animals or plants with which it comes into direct contact. Whether this term expresses it or not, the distinction is a fundamental one. Whether with the cecologist we regard the organism in relation to the world, or with the physiologist as a wonderful complex of vital energies, the two branches have this in common, that both studies fix their attention, not on stuffed animals, butterflies in cases, or even microscopical sections of the animal or plant body-all of which relate to the framework of life-but on life itself.

19 2

The conception of biology which was developed by Treviranus as far as the knowledge of plants and animals which then existed rendered possible, seems to me still to express the scope of the science. I should have liked, had it been within my power, to present to you both aspects of the subject in equal fulness; but I feel that I shall best profit by the present opportunity if I derive my illustrations chiefly from the division of biology to which I am attached-that which concerns the internal relations of the organism, it being my object not to specialise in either direction, but as Treviranus desired to do, to regard it as part-surely a very important part-of the great science of nature.

The origin of life, the first transition from non-living to

Bausner, De Consensu Partium Humani Corporis, Amst., 1556, Præf. ad lectorem, P. 4.

These he identifies with "those complicated mutual relations which Darwin designates as conditions of the struggle for existence." Along with chrology-the distribution of animals-acology constitutes what he calls Relations physiologie. Haeckel, "Entwickelungsgang u. Aufgaben der Zoologie," Jenaische Zeitschr. vol. v. 1869. p. 353.

No seriously

living, is a riddle which lies outside of our scope. minded person, however, doubts that organised nature as it now presents itself to us has become what it is by a process of gradual perfecting or advancement, brought about by the elimination of those organisms which failed to obey the fundamental principle of adaptation which Treviranus indicated. Each step, therefore, in this evolution is a reaction to external influences, the motive of which is essentially the same as that by which from moment to moment the organism governs itself. And the whole process is a necessary outcome of the fact that those organisms are most prosperous which look best after their own welfare. As in that part of biology which deals with the internal relations of the organism, the interest of the individual is in like manner the sole motive by which every energy is guided. We may take what Treviranus called selfish adaptation-Zweckmässigkeit für sich selber-as a connecting link between the two branches of biological study. Out of this relation springs another which I need not say was not recognised until after the Darwinian epoch-that I mean, which subsists between the two evolutions, that of the race and that of the individual. Treviranus, no less distinctly than his great contemporary Lamarck, was well aware that the affinities of plants and animals must be estimated according to their developmental value, and consequently that classification must be founded on development; but it occurred to no one what the real link was between descent and development; nor was it, indeed, until several years after the publication of the "Origin" that Haeckel enunciated that "biogenetic law," according to which the development of any individual organism is but a memory, a recapitulation by the individual of the development of the race-of the process for which Fritz Müller had coined the excellent word "phylogenesis"; and that each stage of the former is but a transitory reappearance of a bygone epoch in its ancestral history. If, therefore, we are right in regarding ontogenesis as dependent on phylogenesis the origin of the former must correspond with that of the latter; that is, on the power which the race or the organism at every stage of its existence possesses of profiting by every condition or circumstance for its own advancement.

From the short summary of the connection between different parts of our science you will see that biology naturally falls into three divisions, and these are even more sharply distinguished by their methods than by their subjects; namely, Physiology, of which the methods are entirely experimental; Morphology, the science which deals with the forms and structure of plants and animals, and of which it may be said that the body is anatomy, the soul, development; and finally, Ecology, which uses all the knowledge it can obtain from the other two, but chiefly rests on the exploration of the endless varied phenomena of animal and plant life as they manifest themselves under natural conditions. This last branch of biologythe science which concerns itself with the external relations of plants and animals to each other, and to the past and present conditions of their existence-is by far the most attractive. In it those qualities of mind which especially distinguish the naturalist find their highest exercise, and it represents more than any other branch of the subject what Treviranus termed the "philosophy of living nature. Notwithstanding the very general interest which several of its problems excite at the present moment I do not propose to discuss any of them, but rather to limit myself to the humbler task of showing that the fundamental idea which finds one form of expression in the world of living beings regarded as a whole-the prevalence of the bestmanifests itself with equal distinctness, and plays an equally essential part in the internal relations of the organism in the great science which treats of them-Physiology.

Origin and Scope of Modern Physiology.

Just as there was no true philosophy of living nature until Darwin, we may with almost equal truth say that physiology did not exist as a science before Johannes Müller. For although the sum of his numerous achievements in comparative anatomy and physiology, notwithstanding their extraordinary number and importance, could not be compared for merit and fruitfulness with the one discovery which furnished the key to so many riddles, he, no less than Darwin, by his influence on his successors was the beginner of a new era.

Müller taught in Berlin from 1833 to 1857. During that time a gradual change was in progress in the way in which biologists regarded the fundamental problem of life.

Müller him