All' estin en tois malista koilotata kai megista tôn tou zôou moriôn hê te gastêr kai <hai> mêtrai te kai hysterai kaloumenai. ti oun kôlyei tauta prôta procheirisamenous episkepsasthai tas energeias autôn, hosai men kai pro tês anatomês dêlai, tên exetasin eph' hêmôn autôn poioumenous, hosai d' amydroterai, ta paraplêsia diairountas anthrôpô zôa, || ouch hôs ouk an hikanôs to 147 ge katholou peri tês zêtoumenês dynameôs kai tôn anomoiôn endeixomenôn, all' hôs hin' hama tô koinô kai to idion eph' hêmôn autôn egnôkotes eis te tas diagnôseis tôn nosêmatôn kai tas iaseis euporôteroi gignômetha. Peri men oun amphoterôn tôn organôn hama legein adynaton, en merei d' hyper hekaterou poiêsometha ton logon apo tou saphesteron endeixasthai dynamenou tên kathektikên dynamin arxamenoi. katechei men gar kai hê gastêr ta sitia, mechri per an ekpepsê, katechousi de kai hai mêtrai to embryon, est' an teleiôsôsin; alla pollaplasios estin ho tês tôn embryôn teleiôseôs chronos tês tôn sitiôn pepseôs. III We may expect, then, to detect the retentive faculty in the uterus more clearly in proportion to the longer duration of its activity as compared with that of the stomach. For, as we know, it takes nine months in most women for the foetus to attain maturity in the womb, this organ having its neck quite closed, and entirely surrounding the embryo together with the _chorion_. Further, it is the utility of the function which determines the closure of the os and the stay of the foetus in the uterus. For it is not casually nor without reason that Nature has made the uterus capable of contracting upon, and of retaining the embryo, but in order that the latter may arrive at a proper size. When, therefore, the object for which the uterus brought its retentive faculty into play has been fulfilled, it then stops this faculty and brings it back to a state of rest, and employs instead of it another faculty hitherto quiescent--the _propulsive_ faculty. In this case again the quiescent and active states are both determined by utility; when this calls, there is activity; when it does not, there is rest.