46 THE FUNCTIONS OF LIFE. 



to a regular plan traced by the great Author of the 

 universe for bestowing perfection on his works. 

 This gradation of structure was necessarily accom- 

 panied by a gradation of faculties : the object of 

 each change of type being to attain higher objects, 

 and to advance a further step towards the ultimate 

 ends of the animal creation. Many apparent ano- 

 malies which are inexplicable upon any other 

 supposition, are reconcilable to this theory. The 

 develoj)ements of structure belonging to a parti- 

 cular type, being always prospective, are not com- 

 pleted in the inferior orders of the group formed 

 on that model, but remain more or less imper- 

 fect, although each organ always fully answers the 

 particular purpose of the individual animal. But 

 it sometimes happens that the imperfection of an 

 organ is so great, in consequence of its develope- 

 ment having proceeded to a very small extent, as 

 to render it wholly useless in that particular spe- 

 cies, although in a higher race of animals it fully 

 performs its proper function. Thus we shall find 

 that rudiments of feet are contained within the 

 bodies of various kinds of serpents, which can ob- 

 viously not be serviceable as organs of progression. 

 In the young of the whale, before its birth, there is 

 found in the lower jaw, a row of small teeth, which 

 do not rise above the gums, and can, therefore, be 

 of no use as instruments of mastication. Their 

 further growth is arrested, and they afterwards 

 wholly disappear. This imperfect or riidiinental 

 condition of an organ indicates its relation to other 

 species belonging to the same type, and demon- 

 strates the existence of a general plan in their for- 

 mation. T shall have occasion to mention several 



