38-(8) MINERAL PHYSIOLOGY. 



changes of matter, and it may be said that the whole 

 history of inorganic nature, or of the mineral kingdom, 

 is comprised in its dynamical and chemical relations. It 

 is not until we enter the organic world that we hnd other 

 forms of activity manifested in the phenomena of irrita- 

 bility, assimilation, growth and reproduction, wherein 

 to dynamical and chemical processes are superadded 

 those which are peculiar to the organic world, and which 

 are distinguished as vital or biotical. It is not our 

 plan or purpose to consider in this connection the great 

 question of the nature of life, but I must here record, my 

 conviction that the activities which appear in a growing 

 organism are but manifestations on a higher plane, and 

 with more perfect means, furnished by a more complex 

 structure, of an energy which already existed in the un- 

 organized matter of the mineral kingdom. 



The student who has begun by investigating natural 

 objects in the way which has just been pointed out, will 

 not be content to rest in this knowledge. Having learned 

 the structure, properties and mode of formation of the 

 crystal, and the chemical changes of which its constitu- 

 ents may be the subject, he is led to study the relations 

 of the various parts of the mineral world to each other, 

 to consider their growth, their decay, and their past and 

 their future history. Coming next to the study of the 

 organic world, he finds therein relations still more com- 

 plex ; the beginnings of life, the genesis of organized in- 

 dividuals ; the assimilation by these of extraneous 

 matter, whether from the organic or the inorganic world, 

 which constitutes nutrition, and the mutual interdepend- 

 ence and interaction between the mineral, vegetable and 

 animal kingdoms, engage his attention. Not less won- 

 derful are the laws of growth and reproduction, the mor- 

 phological changes of organisms, and the subtile relations 

 which connect the lowest with the highest forms in or- 

 ganized nature. This study of the laws and processes by 

 which the material world is fashioned gives us the reason 

 or the logic of nature, a phrase synonymous with physi- 

 ology. We have thus presented to us two aspects of the 

 study of nature, the one descriptive, which we designate 

 General Physiography or Natural History, the other 

 philosophical, which is appropriately called General 



