34 SCIENCE OF THE GREEKS. PT. I. 



written more than 500 valuable essays on medicine and the 

 human body. You will remember that Erasistratus and 

 Herophilus dissected the human body ; but in the time of 

 Galen this seems to have been forbidden, and he was obliged 

 to work upon monkeys and other animals. Even from these, 

 however, he learnt some very important facts. For instance, 

 he discovered the difference between the two sets of nerves 

 which we have in our body, called the nerves of sensation 

 and the nerves of motion. 



Our bodies are provided with two sets of fine cords or 

 threads called nerves ; one set running from different parts of 

 the body to the spine and the brain, and the other set run- 

 ning back from the spine and brain to the body. If you 

 touch a hot iron with your finger, the nerves of sensation, 

 that is, of feeling, carry the message to your brain that 

 the iron is hot, and then instantly the nerves of motion 

 carry the message back from your brain to your finger, and 

 you snatch it away. If you were to cut the nerves of your 

 finger you would not feel pain nor draw your finger away. 

 You will remember that Erasistratus had an idea that it is in 

 our brain that we feel ; Galen proved this by many experi- 

 ments, though he did not understand clearly the whole 

 action of the nerves. He also proved that the veins of our 

 body contain blood, and he described the two muscles which 

 by their contraction pull down the lower jaw as we open 

 and pull it up as we shut our mouths. Besides these and 

 many other discoveries, Galen worked out a whole theory of 

 medicine, and how doctors were to treat their patients, and 

 his rules were the guide of physicians for many hundred 

 years. 



Concluding Remarks on Greek Science. We have now 

 come to an end of the science of the Greeks. You will 



