GENERATION OF ANIMALS, II. i. 



Now it makes no difference whether we say " the 

 semen " or " that from which the semen comes," in 

 so far as the semen has within itself the movement 

 which the generator set going. " And it is possible 

 that A should move B, and B move C, and that the 

 process should be like that of the " miraculous " 

 automatic puppets ^ : the parts of these automatons, 

 even while at rest, have in them somehow or other 

 a potentiality, and when some external agency sets 

 the first part in movement, then immediately the 

 adjacent part comes to be "^ in actuality. The cases 

 then are parallel : just as ^^ith the automaton (1) in 

 one way it is the external agency which is causing 

 the thing's movement — \iz., not by being in contact 

 with it anywhere now, but by ha\ing at one time 

 been in contact \vith it, so too that from which the 

 semen originally came, or that which fashioned the 

 semen, (causes the embrj-o's movement) ** — \\z., not 

 by being in contact with it still, but by having once 

 been in contact with it at some point ; (2) in another 

 way, it is the movement resident ■\vithin (which 

 causes it to move), just as the acti\ity of building 

 causes the house to get built.* 



It is clear by now that there is something which 

 fashions the parts of the embryo, but that this agent 

 is not by way of being a definite indi\idual thing,' 

 nor is it present in the semen as something already 

 perfected to begin with. 



To answer the question. How exactly is each of 

 the parts formed ? we must take first of all as our 



<* i.e., development ; see Introd. §§ 47 fF. 



• Cf. above, 730 b 8. 



' ToSc Ti : rf. Met. 1030 a 7 to roh^ rt rals ovaiais virapxei 

 Itovov. A ToSe Ti is often equated with an ovaia. Also cf. 

 P. A. 641 b 31 ye'veffts ftev yap to oTrepfxa, ovaia 8c to reXos. 



151 



