298 Mayow 



The other effect of respiration is that the nitro- 

 aerial particles should, by means of the blood, be 

 carried to the brain in quantity sufficient for the 

 renewal and completion of the animal spirits ; and 

 unless that takes place, a failure of the spirits and 

 swooning will soon follow on the suppression of the 

 other respiration— that of the brain. 



HOW JUMPING IS PRODUCED 



We shall add here as a corollary something as 

 to that motion by which animals lift themselves 

 altogether from the ground and jump. This motion 

 is produced, according to the view of the distinguished 

 Willis, not by the contraction of muscles, but rather 

 by some elastic force. For, indeed, that learned man 

 says in his Answer to Dr Highmore — " Tf there is no 

 attraction except to an immovable part, how can an 

 animal move its whole body and completely lift 

 itself from the ground : surely the motion of the 

 whole follows the motion of the individual motor 

 parts, wherefore if these can be drawn only one 

 towards another and not lift themselves wholly by 

 some elastic power, I confess that I do not understand 

 how and by what further artifices an animal is able 

 to lift itself as a whole and jump hither and thither." 

 But I really cannot conceive what the learned man 

 understands by an elastic force of the organs : there 

 is, however, no reason why we should seek refuge in 

 it, for the motion of animals raising themselves from 

 the ground can be produced quite conveniently by 

 the contraction of the extended muscles, as will be 

 made plain by what follows. For in Plate III., Fig. 6, 

 let a^ 3, be a stick, which we shall suppose to be 



