Sexualandasexualreproductionarethusseennottodifferessentially;andwehavealreadyshownthatasexualreproduction，thepowerofregrowthanddevelopmentareallpartsofoneandthesamegreatlaw。
REGROWTHOFAMPUTATEDPARTS。
Thissubjectdeservesalittlefurtherdiscussion。Amultitudeoftheloweranimalsandsomevertebratespossessthiswonderfulpower。Forinstance，Spallanzanicutoffthelegsandtailofthesamesalamandersixtimessuccessively，andBonnet（27/18。Spallanzani’AnEssayonAnimalReproduction’
translatedbyDr。Maty1769page79。Bonnet’Oeuvresd’Hist。Nat。’tome5part14to。edition1781pages343，350。）didsoeighttimes;andoneachoccasionthelimbswerereproducedontheexactlineofamputation，withnopartdeficientorinexcess。Analliedanimal，theaxolotl，hadalimbbittenoff，whichwasreproducedinanabnormalcondition，butwhenthiswasamputateditwasreplacedbyaperfectlimb。（27/19。VulpianasquotedbyProf。Faivre’LaVariabilitedesEspeces’1868page112。）Thenewlimbsinthesecasesbudforth，andaredevelopedinthesamemannerasduringtheregulardevelopmentofayounganimal。Forinstance，withtheAmblystomalurida，threetoesarefirstdeveloped，thenthefourth，andonthehind—feetthefifth，andsoitiswithareproducedlimb。（27/20。Dr。P。Hoy’TheAmericanNaturalist’September1871page579。）
Thepowerofregrowthisgenerallymuchgreaterduringtheyouthofananimalorduringtheearlierstagesofitsdevelopmentthanduringmaturity。ThelarvaeortadpolesoftheBatrachiansarecapableofreproducinglostmembers，butnotsotheadults。（27/21。Dr。GuntherinOwen’AnatomyofVertebrates’