Kai men ge kai triton ti || genos inôn esti <tôn> loxôn, 181 elatton poly tô plêthei tôn proeirêmenôn dyo genôn. heurisketai d' en men tois ek dyoin chitônôn synestêkosin organois en thaterô monô tais eutheiais isin anamemigmenon, en de tois ex henos hama tois allois dyo genesi. synepilambanousi d' hautai megiston tê tês kathektikês onomastheisês dynameôs energeia; deitai gar en toutô tô chronô pantachothen esphinchthai kai peritetasthai tois enyparchousi to morion, hê men gastêr en tô tês pepseôs, hai mêtrai d' en tô tês kyêseôs chronô panti. Taut' ara kai ho tês phlebos chitôn heis ôn ek polyeidôn inôn egeneto kai tôn tês artêrias ho men exôthen ek tôn strongylôn, ho d' esôthen ek men tôn eutheiôn pleistôn, oligôn de tinôn syn autais kai tôn loxôn, hôste tas men phlebas tais mêtrais kai tais kystesin eoikenai kata ge tên tôn inôn synthesin, ei kai tô pachei leipontai, tas d' artêrias tê gastri. mona de pantôn organôn ek dyoin th' hama kai amphoterôn enkarsias echontôn tas inas egeneto ta entera. to d' hoti beltion ên || tôn t' allôn 182 hekastô toioutô tên physin hyparchein, hoionper kai nyn esti, tois t' enterois ek dyoin homoiôn chitônôn synkeisthai, tês peri chreias moriôn pragmateias estin. oukoun nyn chrê pothein akouein peri tôn toioutôn, hôsper oude dia ti peri tou plêthous tôn chitônôn hekastou tôn organôn diapephônêtai tois anatomikois andrasin. hyper men gar toutôn autarkôs en tois peri tês anatomikês diaphônias eirêtai; peri de tou dioti toiouton hekaston egeneto tôn organôn, en tois peri chreias moriôn eirêsetai. XII It is not, however, our business to discuss either of these questions here, but to consider duly the _natural faculties_, which, to the number of four, exist in each organ. Returning then, to this point, let us recall what has already been said, and set a crown to the whole subject by adding what is still wanting. For when every part of the animal has been shewn to draw into itself the juice which is proper to it (this being practically _the first of the natural faculties_), the next point to realise is that the part does not get rid either of this attracted nutriment as a whole, or even of any superfluous portion of it, until either the organ itself, or the major part of its contents also have their condition reversed. Thus, when the stomach is sufficiently filled with the food and has absorbed and stored away the most useful part of it in its own coats, it then rejects the rest like an alien burden. The same happens to the bladders, when the matter attracted into them begins to give trouble either because it distends them through its quantity or irritates them by its quality.