The Improvement of Human Reason
Exhibited in the Life of Hai Ebn Yokdhan
by Ibn Tufail
§ 24. It happen’d that by Collision a Fire was kindled among a parcel of Reeds or Canes; which fear’d him at first, as being a Sight which he was altogether a Stranger to; so that he stood at a distance a good while, strangely surpriz’d, at last he came nearer and nearer by degrees, still observing the Brightness of its Light and marvellous Efficacy in consuming every thing it touch’d, and changing it into its own Nature; till at last, his Admiration of it, and that innate Boldness and Fortitude, which God had implanted in his Nature prompted him on, that he ventur’d to come near it, and stretch’d out his Hand to take some of it. But when it burnt his Fingers and he found there was no dealing with it that way, he endeavour’d to take a stick, which the Fire had not as yet wholly seiz’d upon; so taking hold on that part which was untouch’d he easily gain’d his purpose, and carried it Home to his Lodging (for he had contriv’d for himself a convenient place) there he kept this Fire and added Fuel to it, admir’d it wonderfully, and tended it night and day; at night especially, because its Light and Heat supply’d the absence of the Sun; so that he was extreamly delighted with it, and reckon’d it the most excellent of all those things which he had about him. And when he observ’d that it always mov’d upwards, he perswaded himself that, it was one of those Celestial Substances which he saw shining in the Firmament, and he was continually trying of its power, by throwing things into it, which he perceiv’d it operated upon and consum’d, sometimes sooner, sometimes slower, according as the Bodies which he put into it were more or less combustible.
§ 25. Amongst other things which he put in to try its strength, he once flung in some Fish which had been thrown a-shore by the Water, and as soon as e’re he smelt the Steam, it rais’d his Appetite, so that he had a Mind to Taste of them; which he did, and found ’em very agreeable and from that time he began to use himself to the Eating of Flesh, and applied himself to Fishing and Hunting till he understood those sports very well: upon this account he admir’d his Fire more and more, because it help’d him to several sorts of Provision which he was altogether unacquainted with before.
§ 26. And now when his Affection towards it was increas’d to the highest degree, both upon the account of its Beneficial Effects, and its Extraordinary Power; he began to think that the Substance which was departed from the Heart of his Mother the Roe, was, if not the very same with it, yet at least of a Nature very much like it. He was confirm’d in his Opinion, because he had observ’d in all Animals, that as long as they liv’d, they were constantly warm without any Intermission, and as constantly Cold after Death, Besides he found in himself, that there was a greater degree of Heat by much in his Breast, near that place where he had made the Incision in the Roe. This made him think that if he could dissect any Animal alive, and look into that Ventricle which he had found empty when he dissected his Dam the Roe, he might possibly find it full of that Substance which inhabited it, and so inform himself whether it were of the Substance with the Fire, and whether it had any Light or Heat in it or not. In order to this he took a Wild Beast and ty’d him down, so that he could not stir, and dissected him after the same manner he had dissected the Roe, till he came to the Heart; and Essaying the left Ventricle first, and opening it, he perceiv’d it was full of an Airy Vapour, which look’d like a little Mist or white Cloud, and putting in his Finger, he found it hotter than he could well endure it, and immediately the Creature Dyed. From whence he assuredly concluded, that it was that Moist Vapour which communicated Motion to that Animal, and that there was accordingly in every Animal of what kind soever, something like it upon the departure of which Death follow’d.
§ 27. He had then a great desire to enquire into the other parts of Animals, to find out their Order and Situation, their Quantity and the manner of there Connexion one with another, and by what means of Communication they enjoy the Benefit of that Moist Vapour, so as to live by it. How that Vapour is continu’d the time it remains, from whence it has its Supplies, and by what Means its Heat is preserv’d. The way which he us’d in this Enquiry was the Dissection of all sorts of Animals, as well Living as Dead, neither did he leave off to make an accurate Enquiry into them, till at length he arrived to the highest degree of Knowledge in this kind which the most Learned Naturalists ever attain’d to.
§ 28. And now he Apprehended plainly that every particular Animal, tho’ it had a great many Limbs, and variety of Senses and Motions, was nevertheless One in respect of that Spirit, whose Original was from one firm Mansion, viz. the Heart, from whence, its Influence was diffus’d among all the Members. And that all the Members were subservient to it, or inform’d and supported by it, and that this Spirit made use of those Members, in the same manner as a Soldier do’s of his Weapons, or an Huntsman or Fisherman of his Tackling, who makes use of different ways and things, according to the difference of the Creatures he intends to catch. Now the Soldiers Weapons are some of ’em defensive and offensive, and the Sportsman’s too are some for Land, and some for Water: So the Anatomists Instruments, are some for Fission, others for Fraction, and others for Perforation. And thus tho’ the Body was One, yet that governing Spirit made use of it several ways, according to the respective uses of each Member, and the several ends which it propos’d to obtain.
§ 29. Thus he perceiv’d that there was all this while but One Animal Spirit, whose Action when he made use of the Eye, was Sight; when of the Ear, Hearing; when of the Nose, Smelling; when of the Tongue, Tasting; and when of the Skin and Flesh, Feeling. When it employ’d any Limb, then its Operation was Motion; and when it made use of the Liver, Nutrition and Concoction. And that, tho’ there were Members fitted to every one of these uses, yet none of them could perform their respective Offices, without having Correspondence with that Spirit, by means of the Nerves; and that if at any time it chanc’d that their passages were either broken off or obstructed, such a Member would be altogether useless. Now these; Nerves derive this Spirit from the Brain, which has it from the Heart (and contains abundance of Spirit, because it is divided into a great many partitions) and by what means soever any limb is depriv’d of his Spirit, it’s Action ceases, and ’tis like a cast off Tool, not fit for use. And if this Spirit depart wholly from the Body, or is consum’d or dissolv’d by any means whatsoever, then the whole Body is depriv’d of Motion all at once, and reduced to a State of Death.