CONCLUSION. 473 



secutive formations probably 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 for a long 

 period unchanged, while within the same period, several of 

 these species, by migrating into new countries and coming 

 into competition with foreign 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 inhabit- 

 ants 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, the}' 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 distinct 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 pro- 

 phetic 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 ulti- 

 mately 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 solelv by and for the good of each being, all corpo- 



