BUT, however, the above-mention’d _Four remarkable Times_ may be also thus distinguished; _viz._ The _first_ perfects the Work of _Spumification_ and _Coagulation_; the _second_ the _Vegetative_; the _third_ the _Sensitive_; and the _fourth_ begins the _Rational Operation_: Altho’ _this_ cannot yet be discern’d, because of the _Redundancy_ of HUMOURS. FROM the beginning of this _Chapter_, ’tis evident that the more _noble_, or _three chief Parts_ take the _first beginning_ to FORMATION, tho’ perhaps last _perfected_, which forthwith distribute their respective _Branches_ to the whole _Body_; as the HEART sends forth the _Arteries_, the LIVER the _Veins_, and the BRAIN the _Spinal Marrow_, with all their other _Dependencies_: And according to _Aristotle_, (who says, _there must be a different_ MATTER _to every different_ FORM); So indeed every distinct _Part_ of the Body is _form’d_ of a different Substance, according to the different _Nature_ and singular _Disposition_ of every particular _Part_. HOWEVER, I shall not here pretend to go much farther in describing the FORMATION, it being more the _Philosopher’s_ than the _Physician’s_ Business: But whatever farther Progress _others_ may attempt, I judge it a most difficult and ambiguous Matter; for who can be so well vers’d in those _Indiscoverables_? Or, who can pretend to know sufficiently what is done in those _Obscurities_? The _Series of Nature_ being profounder than our _Understandings_, is consequently above our nicest and exactest _Scrutinies_: Which Consideration makes me astonished at the _Logical Dissertations_ that some Men offer on these _Principles_, even on the most minute _Particles_, and smallest _Proportions_, rashly and inconsiderately assigning every respective _one_ of these, a _precise definite Time_ for their FORMATION.