mothers before they are born ! as if the male rendered not only the female fruitful, but also impregnated the young which she had conceived; in the same way as our cock fertilizes not merely the hen, but also the eggs which are about to be pro- duced by her.
But this is confidently denied by those physicians who assert that conception is produced from a mixture of the seed of each sex. And hence Fabricius, 1 although he affirms that the seed of the cock ejected in coition never does, nor can, enter the cavity of the womb, where the egg is formed, or takes its increase, and though he plainly sees that the eggs when first commencing in the ovarium are, no less than those which exist in the womb, fecundated by the same act of coition, and that of these no part could arise from the semen of the cock, yet has he supposed that this semen, as if it must needs be present and permanent, is contained during the entire year in the "bursa" of the fruitful hen, and reserved in a (i foramen csecum." This opi- nion we have already rejected, as well because that cavity is found in the male and female equally, as because neither there, nor anywhere else in the hen, have we been able to dis- cover this stagnant semen of the cock ; as soon as it has per- formed its office, and impressed a prolific power on the female, it either escapes out of the body, or is dissolved, or is turned into vapour and vanishes. And although Galen, 2 and all physicians with him, oppose by various reasonings this dissolving of the semen, yet, if they carefully trace the anatomical arrange- ment of the genital parts, and at the same time weigh other proofs of the strongest kind, they must confess that the semen of the male, as it is derived from the testicles through the vasa deferentia, and as it is contained in the vesicula3 seminales, is not prolific unless it be rendered spiritual and effervesce into a frothy nature by the incitement of intercourse or desire. For it is not, as Aristotle 3 bears witness, its bodily form, or fire, or any such faculty, that renders the semen prolific, but the spirit which is contained in it, and the nature which inheres in it, bearing a proportion to the element of the stars. "Where- fore, though we should allow with Fabricius that the semen is retained in the "bursa," yet, when that prolific effervescence or
1 Op. cit. pp. 38, 39. 2 Arist, de Gen. Anim. lib. ii, cap. 3. 3 Ibid.
