LETTER LIII. 



ed together, that notwithstanding the frequent and of- 

 ten sudden and violent agitations and contortions of the 

 body, the interior machanism remains uninjured, and 

 even its nicer motions unimpeded. 



If your leisure permitted you to investigate, and 

 your age enabled you to comprehend the intricacies 

 of anatomical science, I should point out to you all 

 the curious construction and well adapted situation of 

 the brain, the heart, the lungs, the liver, the bladder, 

 the intestines, and other organs of life ; but it suits our 

 present purpose to generalize, rather than to descend 

 to particulars, which would burden the memory with- 

 out illuminating your mind. However, when you 

 contemplate an animal body, you can perfectly com- 

 prehend, and will not forget to notice, the numerous 

 instruments which are put together, and often within 

 a very narrow compass. In the single ounce of mat- 

 ter which composes tke body of a sparrow, we see all 

 the instruments necessary for eating, for digestion, 

 for respiration, for seeing, for hearing, for smelling, 

 for walking, for flying, for the performance of every 

 animal function and of every motion. All the parts 

 of the complicated machine are perfectly appropri- 

 ate, completely adapted to their respective uses, and 

 all disposed with the most exact organization. 



You will, my dear sir, readily confess, that this ge- 

 neral view of the animal frame is sufficient to demon- 

 strate the agency of an All-wise and Almighty me- 

 chanist in its formation. I shall, therefore, in confor- 

 mity to my original design, limit myself chiefly to 

 this general exhibition, and only mention two or three 

 particulars which might possibly escape your atten- 

 tion, although too important to be left unnoticed. 



Of the covering of animals, both quadrupeds and 

 T/olatiles, you have by this time had an opportunity of 

 contemplating the perfect adaptation to their various 

 circumstances of living. I shall therefore only re- 

 mind you, that the furs of all animals are known to 

 grow thicker and warmer in winter than in summer, 

 and in cold than in hot climates. Animals also which, 

 constantly live on dry land, such as bears, foxes, 



