Whether a wind egg, if the male's sperm comes into contact with it, is suited for generation.
Further one inquires whether a wind egg, if the male's sperm comes into contact with it, is suited for generation.
It seems not. Because it is necessary for the male's sperm and the female's menses to mix so that they are suited for generation. But when a wind egg is formed, the male's sperm cannot mix with it, and therefore, etc.
In addition, should a wind egg make contact with some power outside the womb, it is not suited for generation of a fetus; therefore, for the same reason, should it make contact with some power inside, it will not be made fit for generation.
The Philosopher says the opposite.
One must reply that the wind egg has three states: one is before the distinction of the white from the yellow; another is when the white is distinguished from the yellow but yet it is still not enclosed within a hard shell; the third is when the shell has hardened and it is separated, as it were, from the womb. When the wind egg is in the first or second state, however, it can be made fit for generation if it makes contact with the male's sperm, because then it can still be mixed with the sperm in the womb just as if they came together simultaneously in the beginning. If, however, it makes contact with the male's sperm in the third state, then it cannot be made fit for generation, just as it cannot be made fit once it is outside the womb.
With this a solution is apparent to the arguments. For they prove that when the egg's shell is hardened, then contact with the male's sperm cannot make it fit for generation.
Whether female birds can be impregnated by the male's kiss or odor alone.
Further one inquires whether female birds can be impregnated by the male's kiss or odor alone.
1. It seems not. An animal is not generated without a generating and moving cause. But the male's sperm is the moving cause. Since, then, neither a kiss nor an odor is the male's sperm, a female cannot be impregnated by them.
2. In addition, everything that enters the mouth passes into the stomach, where it is changed into another nature.12 What is pure results in nutriment; what is impure is excreted through the bowels. Therefore, if the sperm were emitted into the female's mouth by the male's kiss, and if, along with an odor that came up to the female, the sperm were multiplied, it would still not be fit for generation because the sperm cannot do this before it reaches the womb. But there is no direct pathway either from the stomach or from the sense of smell to the womb. Therefore, etc.
The Philosopher says the opposite about partridges and many other animals, which are impregnated by a kiss or odor alone.
To this, one must reply that birds can be impregnated by a kiss or by an odor alone, but this manner of conception is not suited to generation. The reason for the first [claim] is that the female experiences pleasure from the male's odor or touch or kiss, and her desire for coition is aroused, on account of which she emits menses to the womb's opening. From this menses a wind egg or something like it can be generated in the womb, and so birds can be impregnated by either a kiss or an odor. The reason for the second [claim] is that the male's sperm is to the female's semen just as a potter is to the material for a clay vessel. But the material for a clay vessel does not move itself to the form of a fabricated object, like a pot, without the potter's assistance. Therefore, neither will the female's semen lead itself to the perfected act of [creating an] animal without the male's semen.
1-2. With this a solution to the arguments is apparent. For the first arguments prove that birds cannot be impregnated by a kiss or an odor in such a way that what it has received will achieve an animal's form.
Reason, however, shows with respect to the objection that wind eggs can be generated in this way, and that birds can be impregnated by them.