INTRODUCTORY OBSERVATIONS. 15 



tribes of organic beings, too minute to be indi- 

 vidually cognizable by any of the unaided senses, 

 yet largely influencing our own animal economy, 

 and even composing no unimportant part of the 

 crust of the solid globe ; but of the vegetables 

 that clothe and diversify its soil, of the animated 

 creatures that float in its atmosphere, enliven its 

 surface, or cleave its waters, comparatively few 

 have as yet been rendered in any way subser- 

 vient to human use, fewer still domesticated and 

 made the permanent and regular denizens of 

 our fields or companions of our households. 



The efforts of civilized man towards the ful- 

 filment of this great command have been di- 

 rected almost exclusively to the conquest of the 

 inorganic creation, by the utilization of minerals, 

 by contriving methods for availing himself of 

 the mechanical powers and of natural forces, 

 simply or in cunning combinations, by cutting 

 narrow paths for facilitating travel and tran- 

 sport between distant regions, and by devising 

 means of traversing with certainty and speed 

 the trackless and troubled ocean. 



The proper ravage smelts no ores, and em- 

 ploys those metals only which natural processes 

 have reduced. He binds the blocks of which he 

 rears his rude temples with no cement of arti- 

 ficial stone. He drains no swamps, cuts no 

 roads, excavates no canals, turns no mills by 



