THE HUMAN BODY. 201 



LESSON II. 



GENERAL STRUCTURE OF THE HUMAN BODY. 



OUR body is a wonderful piece of machinery, 

 perfect in all its parts, curious in all its arrange- 

 ment, and admirably fitted for our peculiar wants. 

 We have going on within us, at all times, an 

 infinite variety of singular operations, such as 

 digestion, nutrition, secretion, and circulation; 

 and yet we are not sensible of them, although there 

 are thousands of vessels at work ; some removing 

 parts, some laying down fresh matter, some car- 

 rying black blood, some red blood, some bile, and 

 some watery fluids. 



The heart contracts and expands, and sends a 

 stream of fresh blood through our bodies seventy 

 or eighty times every minute. The lungs are 

 filled with fresh air, and this is returned quite 

 changed above a thousand times every hour, and 

 all these things are done so gently, and by parts 

 so perfectly made, that were we not told of the 

 wonders within us, we should be in ignorance of 

 their existence. Let us, however, inquire about 

 them ; and an examination of our own frames 

 cannot fail to increase our love of God's goodness, 

 and our admiration of his almighty wisdom and 

 power. 



Our bodies consist of solid and fluid parts. The 

 fluids are by far the most plentiful. The body of 



