428 CONCLUSION. [Chap. XV. 



mutual relation of organism to organism, — the improvement of 

 one organism entailing the improvement or the extermination 

 of others ; it follows, that the amount of organic change in the 

 fossils of consecutive formations prohahly serves as a fair measure 

 of the relative, though not actual lapse of time. A number of 

 species, however, keeping in a body might remain f„r a long period 

 unchanged, whilst within the same period, several of these species, 

 by migrating into new countries and coming into competition with 

 foraign associates, might become modified; so that we must not 

 overrate the accuracy of organic change as a measure of time. 



In the future I see open fields for far more important researches. 

 Psychology will be securely based on the foundation already well 

 laid by Mr. Herbert Spencer, that of the necessary acquirement 

 of each mental power and capacity by gradation. Much light will 

 be thrown on the origin of man and his history. 



Authors of the highest eminence seem to be fully satisfied with 

 the view that each species has been independently created. To my 

 mind it accords better with what we know of the laws impressed on 

 matter by the Creator, that the production and extinction of the 

 past and present inhabitants of the world should have been due to 

 secondary causes, like those determining the birth and death of the 

 individual. When I view all beings not as special creations, but 

 as the lineal descendants of some few beings which lived long before 

 the first bed of the Cambrian system was deposited, they seem to 

 me to become ennobled. Judging from the past, we may safely 

 infer that not one living species will transmit its unaltered likeness 

 to a distant futurity. And of the species now living very few will 

 transmit progeny of any kind to a far distant futurity ; for the 

 manner in which all organic beings are grouped, shows that the 

 greater number of species in each genus, and all the species in 

 many genera, have left no descendants, but have become utterly 

 extinct. We can so far take a prophetic glance into futurity as to 

 foretell that it will be the common and widely-spread species, 

 belonging to the larger and dominant groups within each class, 

 which will ultimately prevail and procreate new and dominant 

 species. As all the living forms of life are the lineal descendants of 

 those which lived long before the Cambrian epoch, we may feel 

 certain that the ordinary succession by generation has never once 

 been broken, and that no cataclysm has desolated the whole world. 

 Hence we may look with some confidence to a secure future of 

 great length. And as natural selection works solely by and for the 

 good of each bein^;, all corporeal and mental er-iowinents will tend 

 to progress towards perfection. 



