116 THE MICBOSCOPIST. 



CHAPTER IX. 



THE MICROSCOPE IN BIOLOGY. 



THE science of biology (from /?w<r, life), which treats of 

 the forms and functions of living beings, would be crude 

 and imperfect without the aid of the microscope. What- 

 ever might be learned by general observation, we should 

 miss the fundamental laws of structure and the unity 

 which we now know pervades distant and apparently 

 different organs, as well as distinct species, if we were 

 deprived of the education which microscopy gives the 

 eye and hand. 



The evident differences between living and non-living 

 bodies led to ancient theories of life which are still influ- 

 ential in modern thought, but neither microscope nor 

 scalpel nor laboratory have revealed the mystery which 

 seems ever to beckon us onward to another and entirely 

 different sphere of existence. Hippocrates invented the 

 hypothesis of a principle (<pu<K<;, or nature) which influences 

 the organism and superintends it with a kind of intelli- 

 gence, and to which other principles (tiuvaneis, powers) are 

 subordinated for the maintenance of various functions. 

 This was also the theory of Aristotle, who gave the name 

 of soul (4>vw) to the animating principle. 



Paracelsus and the chemical philosophers, from the 

 fifteenth to the seventeenth century, maintained that all 

 the phenomena of vitality may be explained by chemical 

 laws. To these succeeded the mathematical school under 

 Bellini (A.D. 1645), who taught that all vital functions 

 may be explained by gravity and mechanical impulse. 

 These theories were supplanted by those of the physiolo- 

 gists. Van Helmont revived the Hippocratian idea of a 

 specific agent, which he called archeus. This was more 

 fully elaborated by Stahl, who taught that by the opera- 



