362 ON GENERATION. 



and the nutriment proceed from the mother, and the plastic 

 virtue from the father ; or rather a certain contagion im- 

 mitted during intercourse, or produced and received from him, 

 which in the body of the hen, or in the eggs, either perma- 

 nently excites the matter of the eggs, or attracts nourishment 

 from the female, and concocts and distributes it first for the 

 growth of the eggs, and then for the production of the chicks ; 

 finally, whether from the male proceeds all that has reference 

 to form and life and fecundity, from the female, again, all that 

 is of matter, constitution, place, and nourishment ? For among 

 animals where the sexes are distinct, matters are so arranged, 

 that since the female alone is inadequate to engender an em- 

 bryo and to nourish and protect the young, a male is associated 

 with her by nature, as the superior and more worthy progenitor, 

 as the consort of her labour, and the means of supplying her 

 deficiencies; in the case of the hen, of correcting by his contagion 

 the inferiority of the hypenemic eggs which she produces, and 

 so rendering them prolific. For as the pullet, engendered of an 

 egg, is indebted to that egg for his body, vitality, and principal 

 or generative part, so and in like manner does the egg receive 

 all that is in it from the female, the female in her turn being 

 dependent on the male for her fecundity which is conferred 

 in coition. 



And here we have an opportunity of inquiring, whether the 

 male be the first and principal cause of the generation of the 

 offspring ; or whether the male along with the female are the 

 mediate and instrumental causes of nature itself, or of the first 

 and supreme generator? And such an inquiry is both be- 

 coming and necessary, for perfect science of every kind de- 

 pends on a knowledge of causes. To the full understanding 

 of generation, therefore, it is incumbent on us to mount from 

 the final to the first and supreme efficient cause, and to hold 

 each and every cause in especial regard. 



We shall have occasion to define that which is the first and 

 supreme efficient cause of the chick in ovo by and by, when 

 we treat of that which constitutes the efficient cause [of gene- 

 ration] among animals in general. Here, meantime, we shall 

 see what its nature may be. 



. The first condition, then, of the primary efficient cause of 

 generation, properly so called, is, as we have said, that it be 



