452 



NA TURE 



{Sept. 6, 1883 



separated as to belong to higher groups. The trilobites of the 

 Cumbrian are some of them of few segments, and, so far, 

 embryonic; but the greater part are many-segmented, and very 

 complex. The batrachians of the carboniferous present many 

 characters higher than those of their modern successors, and now 

 appropriated to the true reptiles. The reptdes of the Permian 

 and tnas u-urped some of the preroga'ives of the mammals. 

 The fern--, lycopods, and equisetuins of the Devonian and car- 

 boniferous were, to say the least, not inferior to their modern 

 representatives. The shell-bearing cephalopods of the palaeoz >ic 

 would seem to have possessed strnctures now special to a higher 

 group, that of the cuttle-fishes. The bald and contemptuous 

 negation of these facts by Haeckel and other biologists does not 

 tend to give geologi-ts much confidence in their dicta. 



Again: we are n iw prepared to say that the struggle for 

 existence, however plau ible as a theory, when put before us in 

 connection with the productiveness of animals, and the few sur- 

 vivors of their multitudinoms progeny, has not been the deter- 

 mining cause of the introduction of new species. The periods 

 of rapd introduction of new forms of marine life were not 

 periods of struggle but of expansion,— those periods in which 

 the submergence of continents afforded new and large space for 

 their extension and comfortable subsistence. In like manner 

 it was continental emergence that afforded the opportunity for 

 the introduction of land animals and plants. Further, in con- 

 nection with this, it is now an established conclusion thit the 

 great aggressive fauna, and floras of the continents have originated 

 in the north, some of them within the Arctic circle ; and this in 

 periods of exceptional warmth, when the perpetual summer sun- 

 shine of the Arctic regions coexisted with a warm temperature. 

 The testimony of the rocks thus is, that not struggle, but expan- 

 sion, furnished the requisite conditions for new forms of life, 

 and that the periods of struggle were characteri-ed by depaupera- 

 tion and extinction. 



But we are sometimes told that organisms are merely 

 mechanical, and that the discussions respecting their origin have 

 no significance, any more than if they related to rocks or crystals, 

 because they relate merely to the organism considered as a 

 machine, and not to that which may be supposed to be more 

 important, namely, the great determining power of mind and 

 will. That this is a mere evasion, by which we really gain 

 nothing, will appear from a characteristic extract from an article by 

 an eminent biologist, in the new edition of the "Encyclopaedia 

 Britannica," — a publication which, I am sorry to say, in-tead of 

 its pr iper rile as a repertory of facts, has become a strong 

 partisan, stating extreme and unproved speculations as if they 

 were conclusions of science. The statement referred to is as 

 follows: " A mass of living protoplasm is simply a molecular 

 machine of great complexity, the total results of the working of 

 which, or its vital phenomena, depend on the one hand on its 

 construction, and, on the other, on the energy sup lied to it ; 

 and to speak of vitality a- anything but the name for a series 

 of operations is as if one should talk of the horologity of a 

 clock." It would, I think, scarcely be possible to put into the 

 -ame number of words a greater amount of unscientific assumption 

 and unproved statement than in this sentence. Is "living proto- 

 1 lasm " different in any way from dead protoplasm, and, if so, 

 what causes the difference ? What is a "machine"? Can we 

 c mceive of a self-produced or uncaused machine, or one not 

 intended to work out some definite results? The results of the 

 machine in question are -aid to be "vital phenomena;" certainly 

 most wonderful results, and greater than those of any machine 

 man has yet been able to construct. But why "vital" ? If there 

 is no such thing as life, surely they are merely physical results. 

 Cm mechanical causes produce other than physical effects? To 

 Aristotle, life was "the cause of form in organisms." Is not 

 this quite as likely to be true as the converse proposition? If 

 the vital phenomena depend on the "construction" of the 

 micbine, and the " energy supplied to it," whence this censtruc- 

 t on, and whence this energy ? The illustration of the clock does 

 not help us to answer this question. The construction of the 

 cl >ck depends on its maker, and its energy is derived from the 

 h ind that winds it up. If we can think of a clock which no one 

 has made and which no one winds, a clock constructed by chance, 

 s et ill harmony with the universe by chance, wound up periodic- 

 ally by chance, — we shall then have an idea parallel to that of 

 an organism living, yet without any vital energy or creative law ; 

 but in such a case we should certainly have to assume some ante- 

 ce lent cause, whether we call it " horologity " or by some other 

 name. Perhaps the term " evolution " would serve as well as 



any other, were it not that common sense teaches that nothing 

 can be spontaneously evolved_, out of that in which it did not 

 previously exist. 



There is one other unsolved problem, in the study of life by 

 the geologist, to which it is still necessary to advert. This is 

 the inability of palaeontology to fill up the gaps in the chain of 

 being. In this respect, we are constantly taunted with the 

 imperfection of the record ; but facts show that this is much more 

 complete than is generally supposed. Over long periods of 

 time and many lines of being we have a nearly continuous 

 chain ; and, if this does n it show the tendency desired, the 

 fault is as likely to be in the theory as in the record. On the 

 other hand, the abrupt and simultaneous appearance of new 

 types in many specific and generic forms, and over wide and 

 separate areas at one and the same time, is too often repeated to 

 be accidental. Hence palaeontologists, in endeavouring to 

 establish evolution, have been obliged to assume periods of 

 exceptional activity in the introduction of specie-', alternating 

 with others of stagnation, — a doctrine differing very little from 

 that of special creation as held by the older geologists. 



The attempt has lately been made to account for these breaks 

 by the assumption that the geological record relates only to 

 periods of submergence, and gives no information as to those of 

 elevation. This is manifestly untrue. In so far as marine life 

 is concerned, the periods of submergence are th >se in which 

 new forms abound for very obvious reasons already hinted. 

 But the periods of new forms of land and fresh-water life are 

 those of elevation, and these have their own records and monu- 

 ments, often very rich and ample ; as, for example, the swamps 

 of the carboniferous, the transition from the cretaceous 

 subsidence to the Laramie elevation, the tertiary lake-basins of 

 the west, the terraces and raised beaches of the pleistocene. Had 

 I time to refer in detail to the breaks in the continuity of life 

 which cannot be explained by the imperfection of the record, I 

 could show at least that nature, in this case, does advance per 

 saltum, — by leips, rather than by a slow continuous process. 

 Many able reasoners, as Le Conte in this country, and Mivart and 

 Collard in England, hold this view. 



Here, as elsewhere, a vast amount of steady conscientious 

 work is required to enable us to solve the problems of the history 

 of life. But, if so, the more the hope for the patient student and 

 investigator. I know nothing more chilling to research, or 

 unfavourable to progress, than the promulgation of a dogmatic 

 decision : hat there is nothing to be learned but a merely fortuitous 

 and uncaused succession, amenable to no law, and only to be 

 covered, in order to hide its shapeless and uncertain proportions, 

 by the mantle of bold and gratuitous hypothesis. 



So soon as we find evidence of continents and oceans, we 

 raise the question, " Have these continents existed from the first 

 in their present position and form, or have the land and water 

 changed places in the course of geological time?" In reality 

 both statements are true in a certain limited sense. On the 

 one hand, any geological map whatever suffices to show that the 

 general outline of the existing land began to be formed in the 

 first and oldest crumplings of the crust. On the other hand, the 

 greater put of the surface of the land consists of marine sedi- 

 ments which must have been derived from land that has perished 

 in the process, while all the continental surfaces, except, perhaps, 

 some high peaks and ridges, have been many times submerged. 

 Both of these apparently contradictory statements are true ; and, 

 without assuming both, it is impossible to explain the existing 

 contours and reliefs of the surface. 



In the case of North America, the form of the old nucleus 

 of Laurentian rock in the north already marks out that of the 

 finished continent, and the successive later formations have been 

 laid upon the edges of this, like the successive loads of earth 

 dumped over an embankment. But in order to give the great 

 thickness of the palaeozoic sediments, the land must have been 

 again and again submerged, and for long periods of time. 

 Thus, in one sense, the continents have been fixed ; in another, 

 they have been constantly fluctuating. Hall and Dana have well 

 illustrated these points in so far as eastern North America is 

 concerned. Professor Hull of the Geological Survey of Ireland 

 has recently had the boldness to reduce the fluctuations of land 

 and water, as evidenced in the British Islands, to the form of 

 a series of maps intended to show the physical geography of 

 each successive period. The attempt is probably premature, and 

 has been met with much adverse criticism ; but there can be no 

 doubt that it has an element of tru'h. When we attempt to 

 calculate what could have been supplied from the old eozoic 



