Ithasbeensettled，then，inwhatsensetheembryoandthesemenhavesoul，andinwhatsensetheyhavenot；theyhaveitpotentiallybutnotactually。
Nowsemenisasecretionandismovedwiththesamemovementasthatinvirtueofwhichthebodyincreases（thisincreasebeingduetosubdivisionofthenutrimentinitslaststage）。Whenithasenteredtheuterusitputsintoformthecorrespondingsecretionofthefemaleandmovesitwiththesamemovementwherewithitismoveditself。Forthefemale’scontributionalsoisasecretion，andhasalltheartsinitpotentiallythoughnoneofthemactually；ithasinitpotentiallyeventhosepartswhichdifferentiatethefemalefromthemale，forjustastheyoungofmutilatedparentsaresometimesbornmutilatedandsometimesnot，soalsotheyoungbornofafemalearesometimesfemaleandsometimesmaleinstead。Forthefemaleis，asitwere，amutilatedmale，andthecatameniaaresemen，onlynotpure；
forthereisonlyonethingtheyhavenotinthem，theprincipleofsoul。Forthisreason，wheneverawind—eggisproducedbyanyanimal，theeggsoforminghasinitthepartsofbothsexespotentially，buthasnottheprincipleinquestion，sothatitdoesnotdevelopintoalivingcreature，forthisisintroducedbythesemenofthemale。Whensuchaprinciplehasbenimpartedtothesecretionofthefemaleitbecomesanembryo。
Liquidbutcorporealsubstancesbecomesurroundedbysomekindofcoveringonheating，likethesolidscumwhichformsonboiledfoodswhencooling。Allbodiesareheldtogetherbytheglutinous；thisquality，astheembryodevelopsandincreasesinsize，isacquiredbythesinewysubstance，whichholdstogetherthepartsofanimals，beingactualsinewinsomeanditsanalogueinothers。Tothesameclassbelongalsoskin，blood—vessels，membranes，andthelike，forthesedifferinbeingmoreorlessglutinousandgenerallyinexcessanddeficiency。
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