NERVES, GLANDS, SECRETION. 213 



Does more than one great artery arise from the heart to 

 supply the body ? 



What becomes of it? 



In what manner are the great vessels protected ? 



How does blood flow from an artery, and what is its 

 colour ? 



Can you tell how veins begin 1 



What vessels carry the blood back to the heart ? 



How does blood flow from a vein ? and what is its colour 1 



Where may veins be seen 1 



LESSON VI. 



NERVES GLANDS SECRETION. 



WHEN we examine the great blood vessels, we 

 generally find that they have lying near them 

 white cords. These are nerves. 



All nerves are connected either with the brain 

 or spinal marrow. Like the arteries, they are 

 large at their beginning, and as they remove from 

 it, become smaller and smaller, by sending off 

 branches. These end in the substance of our 

 bodies, in filaments or twigs, so very small, that 

 we should not know of their presence, were it not 

 that the parts are sensible, or possess feeling. 



Nerves are the organs by which we are made 

 acquainted with the world around us. By their 

 means, we feel, see, hear, smell, and taste. If the 

 aerve supplying the tongue is injured, we can no 

 longer perceive that what we eat has any flavour. 



