248 CHANGES OF THE HUMAN BODY. 



Questions. 



What do we see when we look at the front of the eye ? 



What is the iris, and what is the opening through it called 1 



How may we observe the action of the iris ? 



What provision is made that it may move freely ? 



What is the retina, and where is it placed ? 



Can you tell what part of the eye makes us sensible of 

 light, and enables us to see ? 



By what means is the eye protected "? 



What is light, and why do we see an object? 



Can you tell what is needful in order that a picture be 

 formed on the retina 1 



How is the eye accommodated to different degrees of 

 light"? 



Mention one proof of the wonderful perfection of our eyes. 



LESSON XVII. 



CHANGES OF THE HUMAN BODY INFANCY CHILD- 

 HOOD YOUTH MANHOOD AND OLD AGE. 



THE changes that take place in our bodies, as we 

 advance from infancy to old age, are not less curi- 

 ous than instructive. The hand of our Almighty 

 and all-wise Creator is visibly at work upon us, and 

 we find that in every period of life our organs and 

 their actions are wonderfully fitted to our wants 

 and conditions. 



What helpless little creatures we are in the 

 earlier periods of our life, and how totally we are 

 dependent upon the care of others. An infant 

 cannot, for some months, even direct its eyes to 



