QVEST. III. How many principall parts there are.
BY those things which we haue thus at large discoursed, it is manifest to all men, that there is not one, but many principall parts of mans body; it remaineth that we shew you now how many there are. The number wee cannot better aportion, then from the nature and definition of a Principle. First therefore, we must make it appeare (because Physitians heerein doe not agree) what a principall part is.
Galen in his Booke de vsu partium, defineth this principality by Necessity. That is a Principall part, which is of absolute necessity for the life of Man. I will shew you (saith he) by what markes you shall know a principall part, to wit, by the profit it bringes; now the profit of a part is threefold, either it is simply for life, or for better life, or else for the preseruation of them both; and all such parts without doubt, are truly principall. And in the first Chapter of the xiiii. Booke de vsu partium; Nature hath a three-folde scope in the structure of the parts of Mans body. The first is of those which are necessary for life; and such parts are called Principall, as the Braine, the Heart, and the Liuer, &c. We wil ther∣fore define a Principall part to be that which is absolutely necessary for the preseruation of the whole indiuiduum or particular Man.
Argenterius, who in a humor of contradicting Galen, opposeth himselfe vnto him, reie∣cteth this definition; because if a principall part be defined by necessity, the Stomacke, the Loynes, the Spleene, the Bladder and the Kidneyes, will all fall into the reckoning of prin∣cipall parts. For the action of the Stomacke, is necessarie also for life. The motion of the Lunges we cannot misse, no not for a moment of time; the interception of the Vrine is mortall; and therefore the excretion or auoyding thereof, which is accomplished by the Kidneyes and the Bladder is necessary. But he seemeth to me not to haue attained to the thorough vnderstanding of Galens mind: for there is a double necessity of the parts, one ab∣solute for the preseruation of the indiuiduum, another not 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, that is, simply and abso∣lutely, but secundum quid, or hauing reference to the former. The first maketh a part prin∣cipall, as the Braine, the Heart, and the Liuer: the second kinde of necessity is but relatiue or collaterall, by which some parts owe obseruance to the principall, as necessary seruitors vnto them. For example: What necessary and immediate offices do the Lungs, the Kid∣neyes, the Bladder, and the Spleene performe to the arme, the legge, or the stomacke? But the heart giueth them life, the Liuer affoordeth nourishment, and the Braine supplieth them with sence and motion.
This may seeme somewhat obscure to those that are but Catechists in our Art, but by examples we shall make it sufficiently perspicuous. The Liuer is the onely Prince in the lower region or belly, being therein alone absolutely necessary, and at his owne cost, nou∣rishing the whole family of the body; all the other parts within his precinct are made for his vse. The stomack as a seruant ministreth meate vnto him, the bladder of Gaul purgeth away the Choller from that meate, the Spleene drayneth away the Melancholy iuice, and the Kidneyes the serous or whayie humor, all concurring to depure and cleanse it from ex∣crements to his hand. If therefore they be necessary, it is not for the preseruation of the whole Man, but because they be necessary Ministers to assist the Liuer in his worke. A∣gaine, the Heart sitteth in the middle Region as in his pallace, the Lungs, the Midriffe, and all the arteries attending him for his vse, whom he employeth in quickning the whole body;