486 HISTORY OF PHYSIOLOGY. 



such devefopemertt and metamorphosis as are here 

 spoken of, are ideas entirely different from any of 

 those to which the physical sciences have led us in 

 our previous survey; and are, in short, genuine 

 organical or physiological ideas ; real elements of 

 the philosophy oflifa 



We must, however imperfectly, endeavour to 

 trace the application of this idea in the other great 

 department of the world of life ; we must follow 

 the history of animal morphology. 



