2o8 THE REIGN OF LAW. 



plies combination and adjustment founded upon, 

 and carrying into effect, one vast conception. It is 

 only as an Order of Thought that the doctrine of 

 Animal Homologies is intelligible at all. It is a 

 Mental Order, and can only be mentally perceived. 

 For what do we mean when we say that this bone 

 in one kind of animal corresponds to such another 

 bone in another kind of animal ? Corresponds — 

 in what sense ? Not in the method of using it — 

 for very often limbs which are homologically the 

 same are put to the most diverse and opposite 

 uses. To what standard, then, are we referring 

 when we say that such and such two limbs are 

 homologically the same ? It is to the standard of 

 an Ideal Order — a Plan — a Type — a Pattern men- 

 tally conceived. This sounds very recondite and 

 metaphysical ; and yet the habit of referring phy- 

 sical facts to some ideal standard and order of 

 thought is a universal instinct in the human mind. 

 It is one of the earliest of our efforts in endeavour- 

 ing to understand the ohenomena around us. The 

 science of Homologies, as developed by Cuvier 

 and Hunter and Owen and Huxley, is indeed an 

 intricate, almost a transcendental science. Yet Dr 



