Mia men gar eisodos hê dia tou stomatos hapasi tois sitiois, ouch hen de to trephomenon alla pampolla te kai pampoly diestôta. mê toinyn thaumaze to plêthos tôn organôn, hosa threpseôs heneken hê physis edêmiourgêse. ta men gar alloiounta proparaskeuazei tên epitêdeion hekastô moriô trophên, ta de diakrinei ta perittômata, ta de parapempei, ta d' hypodechetai, ta d' ekkrinei, ta d' hodoi tês pantê phoras eisi tôn chrêstôn chymôn, hôst', eiper boulei tas dynameis tês physeôs hapasas ekmathein, hyper hekastou toutôn an eiê soi tôn organôn episkepteon. Archê d' autôn tês didaskalias, hosa || tou telous engys 24 erga te tês physeôs esti kai moria kai dynameis autôn. XI Let us once more, then, recall the actual purpose for which Nature has constructed all these parts. Its name, as previously stated, is _nutrition_, and the definition corresponding to the name is: _an assimilation of that which nourishes to that which receives nourishments_.[65] And in order that this may come about, we must assume a preliminary process of _adhesion_,[66] and for that, again, one of _presentation_.[67] For whenever the juice which is destined to nourish any of the parts of the animal is emitted from the vessels, it is in the first place dispersed all through this part, next it is presented, and next it adheres, and becomes completely assimilated. The so-called white [leprosy] shows the difference between assimilation and adhesion, in the same way that the kind of dropsy which some people call _anasarca_ clearly distinguishes presentation from adhesion. For, of course, the genesis of such a dropsy does not come about as do some of the conditions of atrophy and wasting,[68] from an insufficient supply of moisture; the flesh is obviously moist enough,--in fact it is thoroughly saturated,--and each of the solid parts of the body is in a similar condition. While, however, the nutriment conveyed to the part does undergo presentation, it is still too watery, and is not properly transformed into a _juice_,[69] nor has it acquired that viscous and agglutinative quality which results from the operation of _innate heat_;[70] therefore, adhesion cannot come about, since, owing to this abundance of thin, crude liquid, the pabulum runs off and easily slips away from the solid parts of the body. In white [leprosy], again, there is adhesion of the nutriment but no real assimilation. From this it is clear that what I have just said is correct, namely, that in that part which is to be nourished there must first occur presentation, next adhesion, and finally assimilation proper.