302 Mayow 



But to bring what has been said to bear upon the 

 present matter, when an animal is bent, so as to be 

 in a suitable position for jumping (and we note that 

 to begin jumping it is quite necessary that the animal 

 should first bend itself), and then the extensor muscles 

 contract all at once with a sufficiently powerful 

 impulse, it comes to pass that all the parts of the 

 animal are carried upwards, as follows from what has 

 been said above : but in as far as all the parts of the 

 animal, and thus the animal itself, are, by the action 

 of the said muscles, set in motion upwards, these 

 muscles carry the animal on high for the same reason 

 as projectiles are moved in any direction ; inasmuch 

 as the impressed force of projectiles is nothing else 

 than motion determined in a particular direction in 

 which the thing has-been made to move by some 

 impelling cause. And so far as to muscular motion. 



