THE DOCTRINE OF PROGRESSIVE DEVELOPMENT. 273 



respective totalities. Time, and a succession of forms in 

 gradation and affinity, become elements in the idea of 

 organic creation. It must be seen that the whole pheno- 

 mena thus pass into strong analogy with those attending 

 the production of the individual organism.' 



This last sentence leads us to the special theory pro- 

 posed by the author to account for the existence of the 

 present forms of life. This theory, termed by the writer 

 the theory of ' progressive development,' may be stated in 

 his own words. 



'The several series of animated beings, from the 

 simplest and oldest up to the highest and most recent, 

 are, under the providence of God, the results, first, of an 

 impulse which has been imparted to the forms of life, 

 advancing them in definite times by generation through 

 grades of organisation terminating in the highest 

 dicotyledons and Vertebrata, these grades being few in 

 number and generally marked by intervals of organic 

 character which we find to be a practical difficulty in 

 ascertaining affinities ; second, of another impulse con- 

 nected with the vital forces, tending in the course of 

 generations to modify organic structures in accordance 

 with external circumstances, as food, the nature of the 

 habitat, and the meteoric agencies, these being the 

 'adaptations' of the natural theologian. We may con- 

 template these phenomena as ordained to take place in 

 every situation and at every time where and when the 

 requisite conditions are presented in other orbs as well 

 as in this in any geographical area of this globe which 

 may at any time arise observing only the variations 



due to difference of materials and of conditions.' 



R 



