PROFESSOR HUXLEY'S VIEWS ON EVOLUTION 205 



discussions about the existing condition of the animal and vegetable worlds and the causes which have determined 

 that condition, an argument has been put forward as an objection to evolution, which we shall have to consider very 

 seriously. It is an argument which was first clearly stated by Cuvier in his criticism of the doctrines propounded 

 by his great contemporary, Lamarck. The French expedition to Egypt had called the attention of learned men to 

 the wonderful store of antiquities in that country, and there had been brought back to France numerous mummified 

 corpses of the animals which the ancient Egyptians revered and preserved, and which, at a reasonable computation, 

 must have lived not less than three or four thousand years before the time at which they were thus brought to 

 light. Cuvier endeavoured to test the hypothesis that animals have undergone gradual and progressive modifica- 

 tions of structure, by comparing the skeletons and such other parts of the mummies as were in a fitting state 

 of preservation, with the corresponding parts of the representatives of the same species now living in Egypt. 

 He arrived at the conviction that no appreciable change had taken place in these animals in the course of this 

 considerable lapse of time, and the justice of his conclusion is not disputed. 



" It is obvious that, if it can be proved that animals have endured, without undergoing any demonstrable change 

 of structure, for so long a period as four thousand years, no form of the hypothesis of evolution which assumes 

 that animals undergo a constant and necessary progressive change can be tenable ; unless, indeed, it be further 

 assumed that four thousand years is too short a time for the production of a change sufficiently great to be detected. 



" But it is no less plain that if the process of evolution of animals is not independent of surrounding condi- 

 tions ; if it may be indefinitely hastened or retarded by variations in these conditions ; or if evolution is simply 

 a process of accommodation to varying conditions ; the argument against the hypothesis of evolution based 

 on the unchanged character of the Egyptian fauna is worthless. For the monuments which are coeval with 

 the mummies testify as strongly to the absence of change in the physical geography and the general conditions 

 of the land of Egypt, for the time in question, as the mummies do to the unvarying characters of its living 

 population. 



" The progress of research since Cuvier's time has supplied far more striking examples of the long duration 

 of specific forms of fife than those which are furnished by the mummified ibises and crocodiles of Egypt. A 

 remarkable case is to be found in the neighbourhood of the Falls of Niagara. In the inmaediate vicinity of the 

 whirlpool, and again upon Goat Island, in the superficial deposits which cover the surface of the rocky subsoil in 

 those regions, there are found remains of animals in perfect preservation, and among them shells belonging to 

 exactly the same species as those which at present inhabit the still waters of Lake Erie. It is evident, from the 

 structure of the country, that these animal remains were deposited in the beds in which they occur at a time when 

 the lake extended over the region in which they are found. This involves the conclusion that they hved and 

 died before the Falls had cut their way back through the gorge of Niagara. I beheve I am speaking within the 

 bounds of prudence if I assume that the Falls of Niagara have not retreated at a greater pace than about a foot a 

 year. Six miles, speaking roughly, are 30,000 feet ; .30,000 feet, at a foot a year, gives 30,000 years ; and thus we 

 are fairly justified in concluding that no less a period than this has passed since the shell-fish, whose remains are 

 left in the beds to which I have referred, were living creatures. 



" But there is still stronger evidence of the long duration of certain types. I have already stated that, as we 

 work our way through the great series of the Tertiary formations, we find many species of animals identical with 

 those which live at the present day, diminishing in numbers, it is true, but still existing, in a certain proportion, 

 in the oldest of the Tertiary rocks. Furthermore, when we examine the rocks of the Cretaceous epoch, we find the 

 remains of some animals which the closest scrutiny cannot show to be, in any important respect, different from 

 those which hve at the present time. That is the case with one of the Cretaceous lamp-shells {Terebratuh), which 

 has continued to exist unchanged, or with insignificant variations, down to the present day. Such is the case with 

 the Glohigerinip, the skeletons of which, aggregated together, form a large proportion of our English chalk. Those 

 Glohigerinm can be traced down to the Globi^erinic which live at the surface of the present great oceans, and the 

 remains of which, falling to the bottom of the sea, give rise to a chalky mud. Hence it must be admitted that 

 certain existing species of animals show no distinct sign of modification, or transformation, in the course of a lapse 

 of time as great as that which carries us back to the Cretaceous period ; and which, whatever its absolute measure, 

 is certainly vastly greater than thirty thousand years. 



" There are groups of species so closely allied together, that it needs the eye of a naturahst to distinguish them 

 one from another. If we disregard the small differences which separate these forms, and consider all the species 

 of such groups as modifications of one type, we shall find that, even among the higher animals, some types have 

 had a marvellous duration. In the chalk, for example, there is found a fish belonging to the highest and the most 

 differentiated group of osseous fishes, which goes by the name of Beryx. But the genus Benjx is represented, at 

 the present day, by very closely alhed species which are Hving in the Pacific and Atlantic Oceans. We may go 



