

PREFACE. 



PERHAPS the author of the following work cannot do better than 

 to make an extract or two, by way of Preface, from Dr. DICK, " On 

 Mental Illumination and Moral Improvement," in which he has 

 shown the want of, and the advantages to be derived from, a trea- 

 tise on Comparative and Human Physiology for the instruction of 

 youth. That a work on these subjects is wanted, it is believed 

 every intelligent Instructor is ready to acknowledge ; and whether 

 that here offered to the public will serve the required purpose, 

 must now be submitted to the judgment of others. 



" It is somewhat unaccountable," says Dr. DICK, " and not a little 

 inconsistent, that while we direct the young to look abroad over 

 the surface of the earth, and survey its mountains, rivers, seas, and 

 continents, and guide their views to the regions of the firmament, 

 where they may contemplate the moons of Jupiter, the rings of Saturn, 

 and thousands of luminaries placed at immeasurable distances, * * 

 that we should never teach them to look into themselves, to con- 

 sider their own corporeal structures, the numerous parts of which 

 they are composed ; the admirable functions they perform ; the wis- 

 dom and goodness displayed in their mechanism, and the lessons of 

 practical instruction which may be derived from such contempla- 

 tions." 



Again, the same author, speaking of subjects for Natural The- 

 ology, enumerates " particularly, the curious and admirable mechan- 

 ism displayed in the construction of animated beings, from the mi- 

 croscopic animalcula, ten hundred thousand times less than a visi- 

 ble point, to the elephant and the whale the organs of mastication, 

 deglutition, digestion, and secretion, all differently contrived, accor- 

 ding to the structure of the animal, and the aliments on which they 

 feed the eyes of insects, and the thousands of transparent globules 

 of which they consist the metamorphoses of caterpillars and other 

 insects, and the peculiar organization adapted to each state of their 

 existence the numerous beauties, and minute adaptation in the 

 wings, feet, probosces, and feathers, of gnats and other'insects the 

 respiratory apparatus of fishes, and the nice adaptation of their 

 bodies to the watery fluid in which they pass their existence the 

 construction of birds, their pointed bills to penetrate the air, their 

 flexible tails serving for rudders, the lightness, strength, and tena- 

 city of their feathers, and the whole structure of their bodies adap- 



