ON GENERATION. 343 



we inquire what is the " efficient," the architect, the adviser, 

 but that we likewise venerate and adore the omnipotent Crea- 

 tor and preserver of a work, which has been well entitled a 

 microcosm. We also ask whence this divine something comes, 

 when it arrives, and Avhere it resides in the egg ; this something 

 which is analogous to the essence of the stars, and is near akin 

 to art and intelligence, and the vicar of the Almighty Creator ? 

 From what precedes it will be apparent how difficult it were 

 to enumerate all the efficient causes of the chick ; it is indis- 

 pensable, indeed, in the complete investigation of this subject 

 to refer to a general disquisition ; we could not from the single 

 generation of the chick in ovo, and without clearer light de- 

 rived from investigations extended to other animals, venture 

 on conclusions that should be applicable to the whole animal 

 creation. And this all the more, since Aristotle himself has 

 enumerated such a variety of efficient principles of animals/" 

 for he at one time adduces the e male' l as the principal efficient 

 cause, as that, to wit, in which the reason of the engendered 

 chick resides, according to the axiom ; 2 " all things are made 

 by the same ' univocal :' " at another time he takes ' the male 

 semen ;' 3 or, ' the nature of the male emitting semen :' 4 some- 

 times it is ' that which inheres in the semen/ 5 ' which causes 

 seeds to be prolific, spirit, to wit, and nature in that spirit cor- 

 responding in its qualities to the essence of the stars :' else- 

 where he says it is ' heat / 6 ' moderate heat / 7 ' a certain and 

 proportionate degree of heat / 8 ' the heat in the blood / 9 ' the 

 heat of the ambient air/ 'the winds / 10 'the sun/ 'the heavens/ 

 ' Jupiter / ' the soul / and, somewhere, nature is spoken of 

 by him as ' the principle of motion and rest/ 



Aristotle 11 concludes the discussion on the efficient cause by 

 declaring it " extremely doubtful" whether it be " anything ex- 

 trinsic ; or something inherent in the geniture or semen ; and 

 whether it be any part of the soul, or the soul itself, or some- 

 thing having a soul?" 



1 Metaphys. lib. i, c. 2 ; lib. iv, c. 1. 7 De Gen. Anim. lib. iv, cap. 2. 



2 Ib. lib. vii, cap. x. 8 Ibid. lib. iv, cap. 4. 



3 De Part. Anim. lib. i, cap. 1. 9 De Part. Anim. lib. ii, cap. 2. 



4 De Gen. Anim. lib. i, cap. 20. 10 De Gen. Anim. lib. iv, cap. 2 ; et De 



5 Ibid. lib. ii, cap. 3. Gen. et cor. lib. ii, tit. 30. 



'' Ibid. lib. v, cap. 3. " De Gen. Anim. lib. ii. cap. 1. 



