74 OiN THE STUDY OF PHYSIOLOGY. 



into the Divinity. Some of the Greeks adopted a distinct 

 vital, sensitive, and rational principle in man. 



These are merely specimens ; a few articles, as patterns, 

 selected from a vast assortment. If you do not like either 

 of them, there are plenty more to choose from. As these 

 and a hundred other such hypothesis are all supported by 

 equally good proof — which is neither more nor less, in each 

 instance, than the thorough conviction of the inventor ; 

 and as they are inconsistent with each other, and there- 

 fore mutually destructive, we need not trouble ourselves 

 further until their respective advocates can agree together 

 in selecting some one for their patronage, and discarding 

 the rest. For of these, as of the numerous religions in the 

 world, only one can be true. 



What is comparative anatomy ? The expression is rather 

 vague and indefinite. You naturally inquire what is 

 compared? what is the object of comparison ? The struc- 

 ture of animals may be compared to that of man. To lay 

 down the laws of the animal economy from facts furnished 

 by the human subject only, would be like writing the natu- 

 ral history of our species from observing the inhabitants of 

 a single town or village. 



Repeated observations and multiplied experiments on 

 the various tribes of animated nature, have cleared up many 

 obscure and doubtful phenomena in the economy of man; 

 a continuation of this method will place physiology on the 

 solid basis of experience, and build up science on ground 

 hitherto occupied by fancy and conjecture. 



The physiologist, who is conversant with natural history 

 In general, is fortified against uncertain opinions, and the 

 showy but flimsy textures of verbal sophistry. An hypo- 

 thesis, which to others appears perfectly adequate to the 

 object in view, is not convincing to him. He rises above 

 the particular object to which it is accommodated, in order 

 to appreciate its value ; as we ascend an eminence to gain 

 a commanding view of a district, to distinguish its features, 

 to ascertain the number and bearings of its parts, and then: 

 relations to the surrounding country. 



