He advocated the formation of coal from the slow but sure accumulation of peatgrowth, as that mode of conservation of vegetable matter was proved to be the most certain to yield pure hydrocarbons such as we find the coal to consist of, unmixed with foreign matter. Such pure accumulations could not (in the opinion of the author) be formed in river-valleys, deltas of great rivers, or in marine swamps and marshes, but on wide plains covered with a thick vegetation, and tending, by its clayey soil, to check drainage and produce peat-growth.

Mr. Woodward referred to the discoveries of Devonian land-plants and insects by Dr. Dawson in North America, and to the occurrence of seed-spores of landplants in Silurian strata; he suggested that the veins of Graphite may be accepted as evidence of old coal-seams, altered by heat and pressure; and that the oilsprings in the Silurian rocks may be due to the destructive distillation of old coalbeds in Nature's own retort.

BIOLOGY.

Address by Dr. ALLEN THOMSON, F.R.SS. L. & E., Professor of Anatomy in the University of Glasgow, President of the Section.

IN now opening the Meetings of the Biological Section, it is my first duty to express my deep sense of the honour which has been conferred upon me in appointing me to preside over its deliberations. I trust that my grateful acceptance of the office will not appear to be an assumption on my part of more than a partial connexion with the very wide field of science included under the term Biology. I should gladly have embraced the opportunity now afforded me of conforming to a custom which has of late become almost the rule with the Presidents of Sections, viz. that of bringing under your review a notice of the more valuable discoveries with which our science has been enriched in recent times, were it not that the subjects which I might have been disposed to select would require an amount of detail in each which would necessarily limit greatly their number, and that any attempt to overtake the whole range of this widespread department of science, even in the most general remarks, would be equally presumptuous and futile on the part of one whose attention has been restricted mainly to one of its divisions. I am further embarrassed in the choice of topics for general remark by the circumstance that many of those upon which I might have ventured to address you have been most ably treated of by my predecessors, as, for example, in the Sectional Addresses of Dr. Acland, Dr. Sharpey, Mr. Berkeley, Dr. Humphry, and Dr. Rolleston, as well as in the General Presidential Addresses of Dr. Hooker and Professor Huxley. I must content myself, therefore, with endeavouring to convey to you some of the ideas which arise in my mind in looking back from the present upon the state of Biological Science at the time when, forty years since, the Meetings of the British Association commenced-a period which I am tempted to particularize from its happening to coincide very nearly with that at which I began my career as a public teacher in one of the departments of Biology in this city. In the few remarks which I shall make, it will be my object to show the prodigious advance which has taken place not only in the knowledge of our subject as a whole, but also in the ascertained relation of its parts to each other, and in the place which Biological knowledge has gained in the estimation of the educated part of the community, and the consequent increase in the freedom with which the search after truth is now asserted in this as in other departments of science.

And first, in connexion with the distribution of the various subjects which are included under this Section, I may remark that the general title under which the whole Section D has met since 1866, viz. Biology, seems to be advantageous both from its convenience, and as tending to promote the greater consolidation of our science, and a juster appreciation of the relation of its several parts. It may be that, looking merely to the derivation of the term, it is strictly more nearly synony

mous with physiology in the sense in which that word has been for a long time employed, and therefore designating the science of life, rather than the description of the living beings in which it is manifested. But until a better or more comprehensive term be found, we may accept that of biology under the general definition of "the science of life and of living beings," or as comprehending the history of the whole range of organic nature-vegetable as well as animal. The propriety of the adoption of such a general term is further shown by a glance at the changes which the titles and distribution of the subordinate departments of this Section have undergone during the period of the existence of the Association.

During the first four years of this period the Section met under the combined designation of Zoology and Botany, Physiology and Anatomy-words sufficiently clearly indicating the scope of its subjects of investigation. In the next ten years a connexion with Medicine was recognized by the establishment of a subsection or department of Medical Science, in which, however, scientific anatomy and physiology formed the most prominent topics, though not to the exclusion of more strictly medical and surgical or professional subjects. During the next decade, or from the year 1845 to 1854, we find along with Zoology and Botany a subsection of Physiology, and in several years of the same time along with the latter a separate department of Ethnology. In the eleven years which extended from 1855 to 1865, the branch of Ethnology was associated with Geography in Section E. More recently, or since the arrangement which was commenced in 1866, the Section Biology has included, with some slight variation, the whole of its subjects in three departments. Under one of these are brought all investigations in Anatomy and Physiology of a general kind, thus embracing the whole range of these sciences when without special application. A second of these departments has been occupied with the extensive subjects of Botany and Zoology; while the third has been devoted to the subject of Anthropology, in which all researches having a special reference to the structure and functions or life-history of man have been received and discussed. Such I understand to be the arrangement under which we shall meet on this occasion. At the conclusion of my remarks, therefore, the department of Anatomy and Physiology will remain with me in this room; while that of Zoology and Botany, on the one hand, and of Anthropology on the other, will adjourn to the apartments which have been provided for them respectively.

With regard to the position of Anthropology, as including Ethnology, and comprehending the whole natural history of man, there may be still some differences of opinion, according to the point of view from which its phenomena are regarded: as by some they may be viewed chiefly in relation to the bodily structure and functions of individuals or numbers of men; or as by others they may be considered more directly with reference to their national character and history, and the affinities of languages and customs; or by a third set of inquirers, as bearing more immediately upon the origin of man and his relation to animals. As the first and third of these sets of topics entirely belong to Biology, and as those parts of the second set which do not properly fall under that branch may with propriety find a place under Geography or Statistics, I feel inclined to adhere to the distinct recognition of a department of Anthropology, in its present form; and I think that the suitableness of this arrangement is apparent, from the nature and number of the appropriate reports and communications which have been received under the last distribution of the subjects.

The beneficial influence of the British Association in promoting biological research is shown by the fact that the number of the communications to the Sections, received annually has been nearly doubled in the course of the last twenty years. And this influence has doubtless been materially assisted by the contributions in money made by the Association in aid of various biological investigations; for it appears that, out of the whole sum of nearly £34,500 contributed by the Association to the promotion of scientific research, about £2800 has been devoted to biological purposes, to which it would be fair to add a part at least of the grants for Paleontological researches, many of which must be acknowledged to stand in close relation to Biology.

The enormous extent of knowledge and research in the various departments of Biology has become a serious impediment to its more complete study, and leads to

the danger of confined views on the part of those whose attention, from necessity or taste, is too exclusively directed to the details of one department, or even, as often happens, to a subdivision of it. It would seem, indeed, as if our predecessors in the last generation possessed this superior advantage in the then existing narrower boundaries of knowledge, that it was possible for them to overtake the contemplation of a wider field, and to follow out researches in a greater number of the sciences. To such combination of varied knowledge, united with their transcendent powers of sound generalization and accurate observation, must be ascribed the widespread and enduring influence of the works of such men as Haller, Linnæus, Cuvier, Von Baer, and Johannes Müller. There are doubtless brilliant instances in our own time of men endowed with similar powers; but the difficulty of bringing these powers into effectual operation in a wide range is now so great, that, while the amount of research in special biological subjects is enormous, it must be reserved for comparatively few to be the authors of great systems, or of enduring_broad and general views which embrace the whole range of biological science. It is incumbent, therefore, on all those who are desirous of promoting the advance of biological knowledge to combat the confined views which are apt to be engendered by the too great restriction of study to one department. However much subdivision of labour may now be necessary in the original investigation and elaboration of new facts in our science (and the necessity for such subdivision will necessarily increase as knowledge extends), there must be secured at first, by a wider study of the general principles and some of the details of collateral branches of knowledge, that power of justly comparing and correlating facts which will mature the judgment and exclude partial views. To refer only to one bright example, I might say that it can scarcely be doubted that it is the unequalled variety and extent of knowledge, combined with the faculty of bringing the most varied facts together in new combination, which has enabled Dr. Darwin (whatever may be thought otherwise of his system) to give the greatest impulse which has been felt in our own times to the progress of biological views and thought; and it is most satisfactory to observe the effect which this influence is already producing on the scientific mind of this country, in opposing the tendency perceptible in recent times to the too restricted study of special departments of natural history. I need scarcely remind you that for the proper investigation and judgment of problems in physiology, a full knowledge of anatomy in general, and much of comparative anatomy, of histology and embryology, of organic chemistry and of physics, is indispensable as a preliminary to all successful physiological observation and experiment. The anatomist, again, who would profess to describe rationally and correctly the structure of the human body, must have acquired a knowledge of the principles of morphology derived from the study of comparative anatomy and development, and he must have mastered the intricacies of histological research. The comparative anatomist must be an accomplished embryologist in the whole range of the animal kingdom, or in any single division of it which he professes to cultivate. The zoologist and the botanist must equally found their descriptions and systematic distinctions on morphological, histological, and embryological data. And thus the whole of these departments of biological science are so interwoven and united that the scientific investigation of no one can now be regarded as altogether separate from that of the others. It has been the work of the last forty years to bring that intimate connexion of the biological sciences more and more fully into prominent view, and to infuse its spirit into all scientific investigation. But while in all the departments of biology prodigious advances have been made, there are two more especially which merit particular mention as having almost taken their origin within the period I now refer to, as having made the most rapid progress in themselves, and as having influenced most powerfully and widely the progress of discovery, and the views of biologists in other departments-I mean Histology and Embryology.

I need scarcely remind those present that it was only within a few years before the foundation of the British Association that the suggestions of Lister in regard to the construction of achromatic lenses brought the compound microscope into such a state of improvement as caused it to be restored, as I might say, to the place which the more imperfect instrument had lost in the previous century. The re

sult of this restoration became apparent in the foundation of a new era in the knowledge of the minute characters of textural structure, under the joint guidance of Robert Brown and Ehrenberg, with contributions from many other observers, so as at last to have almost entitled this branch of inquiry to its designation, by Mr. Huxley, of the exhaustive investigation of structural elements. All who hear me are aware of the influence which, from 1839 onwards, the researches of Schwann and Schleiden exerted on the progress of Histology and the views of anatomists and physiologists as to the structure and development of the textures both of plants and animals, and the prodigious increase which followed in varied microscopic observations. It is not for me here even to allude to the steps of that rapid progress by which a new branch of anatomical science has been created; nor can I venture to enter upon any of the interesting questions presented by this department of microscopic anatomy; nor attempt to discuss any of those difficult problems possessing so much interest at the present moment, such as the nature of the organized cell or the properties of protoplasm. I would only remark that it is now very generally admitted that the cell-wall (as Schwann indeed himself pointed out) is not a constant constituent of the cell, nor a source of new production, though still capable of considerable structural change after the time of its first formation. The nucleus has also lost some of the importance attached to it by Schwann and his earlier followers, as an essential constituent of the cell, while the protoplasm of the cell remains in undisputed possession of the field as the more immediate seat of the phenomena of growth and organization, and of the contractile property which forms so remarkable a feature of their substance. I cordially agree with much of what Mr. Huxley has written on this subject in 1853 and 1869. The term physical basis of life may perhaps be in some respect objectionable; but I look upon the recognition of protoplasm which he has enforced as a most important step in the recent progress of histology, adopting this general term to indicate that part of the organized substance of plants and animals which is the constant seat of the growing and moving powers, but not implying identity of nature and properties in all the variety of circumstances in which it may occur. To Haeckel the fuller history of protoplasm in its lowest forms is due. To Dr. Beale we owe the minutest and most recent investigation of these properties by the use of magnifying-powers beyond any that had previously been known, and the successful employment of reagents which appear to mark out its distinction from the other elements of the textures. I may remark, however, in passing, that I am inclined to regard contractile protoplasm, whether vegetable or animal, as in no instance entirely amorphous or homogeneous, but rather as always presenting some minute molecular structure which distinguishes it from parts of glassy clearness. Admitting that the form it assumes is not necessarily that of a regular cell, and may be various and irregular in a few exceptional instances, I am not on that account disposed to give up definite structure as one of the universal characteristics of organization in living bodies. I would also suggest that the terms formative and non-formative, or some other such, would be preferable to those of "living and dead," employed by Dr. Beale to distinguish the protoplasm from the cell-wall or its derivatives, as these latter terms are liable to introduce confusion.

To the discoveries in embryology and development I might have been tempted to refer more at large, as being those which have had, of all modern research, the greatest effect in extending and modifying biological views, but I am warned from entering upon a subject in which I might trespass too much on your patience. The merits of Wolff as the great leader in the accurate observation of the phenomena of development were clearly pointed out by Mr. Huxley in his presidential address of last year. Under the influence of Döllinger's teaching, Pander, and afterwards Purkinje, Von Baer, and Rathke, established the foundations of the modern history of embryology. It was only in the year 1827 that the ovum of mammals was discovered by Von Baer; the segmentation of the yelk, first observed by Prevost and Dumas in the frog's ovum in 1824, was ascertained to be general in succeeding years; so that the whole of the interesting and important additions which have followed, and have made the history of embryological development a complete science, have been included within the eventful

* Under the appropriate name of "bioplasm."

period of the life of this Association. I need not say how distinguished the Germans have been by their contributions to the history of animal development. The names of Valentin, R. Wagner, Bischoff, Reichert, Kölliker, and Remak are sufficient to indicate the most important of the earlier steps in recent progress, without attempting to enumerate a host of others who have assisted in the great work thus founded.

I am aware that the mere name of development suggests to some ideas of a disturbing kind as being associated with the theory of evolution recently promulgated. To one accustomed during the whole of his career to trace the steps by which every living being, including man himself, passes from the condition of an almost imperceptible germ, through a long series of changes of form and structure into their perfect state, the name of development is suggestive rather of that which seems to be the common history of all living beings; and it is not wonderful therefore that such a one should regard with approval the more extended view which supposes a process of development to belong to the whole of nature. How far that principle may be carried, to what point the origin of man or any animal can by facts or reasoning be traced in the long unchronicled history of the world, and whether living beings may arise independently of parents or germs of previously existing organisms, or may spring from the direct combination of the elements of dead matter, are questions still to be solved, and upon which we may expect this Section to guide the hesitating opinion of the time. I cannot better express the state of opinion in which I find myself in regard to the last of these problems, than by quoting the words of Professor Huxley from his address of last year, p. lxxxiii :"But though I cannot express this conviction of mine too strongly [viz. that the evidence of the most careful experiments is opposed to the occurrence of spontaneous generation], I must carefully guard myself against the supposition that I intend to suggest that no such thing as abiogenesis ever has taken place in the past, or ever will take place in the future. With organic chemistry, molecular physics, and physiology yet in their infancy, and every day making prodigious strides, I think it would be the height of presumption for any man to say that the conditions under which matter assumes the properties we call 'vital, may not, some day, be artificially brought together." And again, "If it were given me to look beyond the abyss of geologically recorded time to the still more remote period when the earth was passing through physical and chemical conditions, which it can no more see again than a man can recall his infancy, I should expect to be a witness of the evolution of living protoplasm from not living matter." I will quote further a few wise words from the discourse to which many of you must have listened last evening with admiration. Sir William Thomson said:"The essence of science, as is well illustrated by astronomy and cosmical physics, consists in inferring antecedent conditions, and anticipating future evolutions, from phenomena which have actually come under observation. In biology, the difficulties of successfully acting up to this ideal are prodigious. Our code of biological law is an expression of our ignorance as well as of our knowledge." And again, "Search for spontaneous generation out of inorganic materials; let any one not satisfied with the purely negative testimony of which we have now so much against it, throw himself into the inquiry. Such investigations as those of Pasteur, Pouchet, and Bastian are among the most interesting and momentous in the whole range of natural history, and their results, whether positive or negative, must richly reward the most careful and laborious experimenting."

The consideration of the finest discoverable structures of the organized parts of living bodies is intimately bound up with that of their chemical composition and properties. The progress which has been made in organic chemistry belongs not only to the knowledge of the composition of the constituents of organized bodies, but also to the manner in which that composition is chemically viewed. Its peculiar feature, especially as related to biological investigation, consists in the results of the introduction of the synthetic method of research, which has enabled the chemist to imitate or to form artificially a greater and greater number of the organic compounds. In 1828 the first of these substances was formed by Wöhler, by a synthetic process, as cyanate of ammonia. But still, at that time, though a few no doubt entertained juster views,