GENERATION OF ANIMALS, IV. x. 



generation and perfecting. As we know, it is heat 

 and cooling in their various manifestations which 

 up to a certain due proportion " bring about the 

 generation of things, and beyond that point their 

 dissolution : and the Uniits of these processes, both 

 as regards their beginning and their end, are con- 

 trolled bv the movements of these heavenly bodies.'' 

 Just as we observe that the sea and whatever is of a 

 fluid nature remains settled or is on the move accord- 

 ing as the winds are at rest or in motion, while the 

 behaviour of the air and the winds in turn depends 

 upon the period of the sun and moon,*^ so too the 

 things which grow out of them and are in them are 

 bound to follow suit (as it is only reasonable that the 

 periods of things of inferior standing should follow 

 those which belong to things of higher standing) 

 since even the ^-ind has a sort of lifespan ** — a genera- 

 tion and a decline. And as for the revolution of 

 these heavenly bodies, there may very well be other 

 principles which Ue behind them.* Nature's aim, 

 then, is to measure the generations and endings 

 of things by the measures of these bodies, but she 



* Cf. 738 a -20 : the times about new moon (at rwv yL-qvotv 

 owoSot) are cold l)ecause of the faiHng of the moon, and for 

 the same reason they are stormier than the middle points of 

 the month : a precisely similar statement, using exactly the 

 same terminology that Aristotle uses, is found twice in 

 Theophr. De vent is 17 and De slgnis 5: in the latter passage 

 the cause given is that the moon's light '' fails "' (aTroAei'irei) 

 from the fourth day of the waning moon until the fourth day 

 of the new moon, and this apparently is the time covered by 

 at avvohoi. tuiv fXT)vu>v. The way in which the sun determines 

 the weather is discussed at Meteor. 359 b -26 if. 



•^ Cf. above, 776 b 1, and Plato, Timaeus 91 b, c, where 

 the course of a disease is compared with the lifespan of a 

 living organism. ' See, e.g., De caelo I, II. 



R 481 



