Atigust 1 6, 1877] 



NATURE 



303 



first produced in the minds of those to whom they were equally 

 unfamiliar and suspicious ; and that even in popular literature 

 and ephemeral effusions, direct or metaphorical illustrations are 

 drawn in such terms of the Darwinian theory as " struggle for 

 existence," "natural selection," "survival of the fittest, ' "here- 

 dity," " atavism," and the like. 



It cannot be doubted that in this country, as on the Continent, 

 the influence of authority had much to do with the persistence of 

 the older teleological views ; and, as has been well remarked by 

 Hackel, one of the ablest and keenest supporters of the modern 

 doctrine, the combined influence more especially of the opinions 

 held by three of the greatest naturalists and biologists who have 

 ever lived, viz., Linnxus, Haller, and Cuvier, men unsurpassed 

 in the learning of their time, and the authors of important dis- 

 coveries in a wide range of biological science, was decidedly 

 adverse to the free current of speculative thought upon the more 

 general doctrines of biology. And if it were warrantable to 

 attribute so great a change of opinion as that to which I have 

 adverted as occurring in my own time, to the influence of any 

 single intellect, it must be admitted that it is justly due to the vast 

 range and accuracy of his knowledge of scientific fads, the quick 

 appreciation of their mutual interdependence, and above all the 

 unexampled clearness and candour in statement of Charles 

 Darwin. 



But while we readily acknowledge the large share which 

 Darwin has had in guiding scientific thought into the newer 

 tracks of biological doctrine, we shall also be disposed to allow 

 that the slow and difficult process of emancipation from the 

 thraldom of dogmatic opinion in regard to a system of creation, 

 and the adoption of large and independent views more con- 

 sistent with observation, reason, philosophy, and religion, has 

 only been possible under the effect of the (general progress of 

 scientific knowledge and the acquisition of sounder methods of 

 applying its principles to the explanation of natural phenomena. 



I have already referred to Goethe, Oken, Lamarck, and Geof- 

 frey St. Hilaire as among the most prominent of the earlier 

 pioneers in the modern or reformed conceptions of biological 

 laws. But were it desirable to mark the progress of opinion by 

 quoting other authors and labourers whose contributions have 

 mainly supplied the materials out of which the new fabric has 

 been constructed, I should have to produce a long catalogue of 

 distinguished names, among which would be found lliose of Lyell 

 and Owen, as earliest shaping the doctrines and guiding opinion 

 in this country, Johannes Miiller and von Baer, as taking the 

 places of Haller and Cuvier on the Continent ; and a host of 

 other faithful workers in Biology belonging to the earlier part of 

 this century, such as those of G. Trevlranus, J. F. Meckel, 

 Carus, and many more.' To Huxley more especially, and to 

 Herbert Spencer, the greatest influence on British thought in the 

 same direction is to be ascribed. 



Let us hope that in these times, when it has been found neces- 

 sary to modify the older teleological views to so great an extent, 

 although there may still be much that is unknown, and wide 

 differences of opinion in regard to the nature and sequence of 

 natural phenomena and the mode of their interpretation, all 

 naturalists will now concur in one important principle, viz., that 

 truthful observation and candid judgment must alone be our 

 guides in the interpretation of nature, and that that theory of 

 creation is most deserving of our adoption which is most con- 

 sistent with the whole body of facts carefully observed and com- 

 pared. 



To attempt to trace, within the limits to which my remarks 

 must be confined, the influence which the progress of knowledge 

 has exercised upon the scientific and general conception of 

 biological doctrines would be impossible, for the modification of 

 opinion on these subjects has proceeded not less from the rapid 

 advance which our age has witnessed in the progress of general 

 science, especially of physics and chemistry, than from that of 

 departments belonging to biology itself. 



Thus, to go no further than the most general laws of nature, 

 the whole doctrine of the conservaiion and transmutation of 

 force in physics, so .ably expounded to this Association by Mr. 

 Justice Grove, the theory of compound radicals and substitution, 

 with the discovery of organic synthesis, in chemistry, and the 

 more recent advance in speculation with regard to the molecular 



' It would also be unjust to omit to mention here one ut the earliest 

 attempts to bring Kritish opinion into a new channel, by the remarkable 

 work entitled " Vestiges of Creation," which appeared in 1S44, nor to conceal 

 from ourselves the unmerited ridicule and obloquy attempted to be thrown 

 upon the author, not perhaps so much on account of the many inaccuracies 

 unavoidable in an attempt at the time to overtake so large a field, as directed 

 against the dangerous tendencies supposed to lurk in its reasoning. 



constitution and properties of matter, with which we must 

 associate the names of our last President and of Clerk Maxwell, 

 in completely changing the aspect of physical and chemical 

 sciences within the last thirty-five years, have paved the way for 

 views of the constitution and (action of organised bodies very 

 different from those which could be formed at the time of the 

 first meeting of the Association in this place. And if, confining 

 ourselves to the department of Biology, we add the discovery by 

 microscopical observation of the minuter elementary forms of 

 organisation, more especially as flowing from the comprehensive 

 views of organised structure promulgated by Schleiden and 

 Schwann nearly forty years ago, the later discovery and investi- 

 gation of living protoplasmic substances, the accumulated 

 evidence of progressive types of animal and vegetable forms in 

 the succession of superimposed strata composing the crust of the 

 earth, the recent discoveries as to the conditions of life at great 

 depths in the ocean, the vast body of knowledge brought together 

 by the labours of anatomists and physiologists as to the structure 

 and functions of almost every plant and animal, and (still more, 

 perhaps, than any other single branch of biological inquiry) if 

 we note the rapid and immense progress which has been made 

 during the last filty years in the study of the entirely modern 

 science of the development of living beings — we shaU be able 

 to form some conception of the enormous extension in our time 

 of the basis of observation and fact from which biological 

 phenomena may now be surveyed, and from which just views 

 may be formed as to their mutual relations and general nature. 



It is now familiarly known that almost all (if not indeed all) 

 the plants and animals existing on the earth's surface derive their 

 origin from parents or previously-existing beings whose form and 

 nature they closely reproduce in their life's history. By far the 

 greater number spring from germs in the form of visible and 

 know-n spores, seeds, or eggs. A few may be traced to germs, 

 or to vestiges of the parental body, the exact nature of which 

 may be doubtful ; and some, including even a certain number of 

 those also produced from known germs, are either constantly or 

 occasionally multiplied by budding, or by a process of cleavage, 

 or direct and visible division of the parent body. 



The germ constituting the basis of new formation, whether it 

 have the form of spore, seed, or ovum, is of the simplest kind 

 of organisation, and the process by which a new plant or animal 

 is produced is necessarily one of gradual change and of advance 

 from a simpler to a more complex form and structure : it is one 

 of "evolution," or, as I would rather name it, "development." 

 But before proceeding to discuss the subject of development in 

 the higher animals, it is right to advert to the preliminary and 

 often debated question, which naturally presents itself, viz. — Do 

 all living or organised beings, without exception, spring from 

 germs, or from any kind of organised matter that has belonged 

 to parents ? or may there not be some, |especi.ally among the 

 simpler lorms (with regard indeed to which alone there has of 

 late been any question), which are produced by the direct com- 

 bination of their component elements, in the way of the so- 

 called spontaneous or equivocal generation, heterogenesis or 

 abiogenesis ? 



The importance of the right solution of this problem is not 

 confined merely to the discovery of the mode of origin of the 

 lowly organisms which have been the more immediate object of 

 investigation by naturalists In recent times, but is one of much 

 wider significance, seeing that, if it shall be satisfactorily proved 

 or even rendered probable that in the course of cosmical 

 development all the various kinds of plants and animals have 

 been gradually produced by evolution out of pre-existing simpler 

 forms, and thus the whole series of organised beings in nature 

 has been shown to be one of hereditary connection and deriva- 

 tion, then it would follow that the history of the origin of the 

 simplest organisms may be the key to that of the first commence- 

 ment of life upon the earth's surface, and the explanation of the 

 relation in which the whole succeeding progenies stand to their 

 parental stocks. 



From the very lucid and masterly view of this subject, given 

 by Prof. Huxley in his address to the Association at Liverpool, 

 so recently as in 1S70, in which the conclusion he formed was 

 based very much on the exhaustive and admirable researches of 

 Pasteur, I might almost have dispensed with making further 

 reference to it now, but for the very confident statements since 

 made by the supporters of the doctrine of abiogenesis, among 

 whom Dr. Bastian stands most prominent in this country, and 

 for the circumstance that the life-history of many of the lower 

 organisms was still imperfectly known. 



During the last seven or eight years, however, renewed inves- 



