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by some other way. For the cavities of tangible things

. do not admit of a vacuum, but are filled either with air or the proper spirit of the thing. But this spirit, whereof I am speaking, is not a virtue, nor an energy, nor an actuality, nor any such idle matter, but a body thin and invisible, and yet having place and dimension, and real. Neither again is this spirit air (no more than wine is water), but a rarefied body, akin to air, though greatly differing from it. Now the grosser parts of bodies, being of a sluggish and not very movable nature, would last for a long time, if this spirit did not disturb, agitate and undermine them, and prey upon the moisture of the body, and whatever else it can turn into fresh spirit ; after which both the preexisting and the newly formed spirit gradually escape together. This is well exhibited by the diminution of weight in bodies dried by perspiration. For it must not be supposed that whatever is emitted either was spirit, when it had weight, or was other than spirit when it had flown.

RULE III. The emission of the spirit produces dryness; the detention and working thereof within the body, either melts, or putrefies, or vivifies.

EXPLANATION. There are four processes of the spirit, namely arefaction, melting, putrefaction and generation of bodies. Arefaction is not properly the work of the spirit, but of the grosser parts after the emission of the spirit; for upon

this they contract themselves, partly to avoid * vacuum and partly from the union of homogeneous things together; as is shown in all things dried by age, and in the drier kinds of bodies which have passed through the fire, as bricks, charcoal, and bread. Melting is the work of the spirits alone, and that only when they are excited by heat; for then the spirits expanding themselves and yet not going forth, insinuate and spread themselves among the grosser parts, and make them soft and molten, as appears in metals and wax; for metals and other tenacious bodies are apt to restrain the spirit, and prevent it from rushing forth when excited. Putrefaction is the combined work of the spirit and the grosser parts. For the spirit (which held together and kept in order the parts of the body) having partly escaped, and partly become feeble, all things are dissolved and return to their heterogeneities, or elements; whatever spirit there was in the body is gathered to itself (whence putrefied bodies begin to have a foul odour); the oily parts are gathered to themselves (and hence putrefied bodies have a certain smoothness and unctuosity); the watery parts likewise to themselves ; and the dregs to themselves (and hence the confusion in putrefied bodies). Generation or vivification is likewise the combined work of the spirit and the grosser parts, but in a very

different manner. For the spirit is entirely detained, but swells and moves locally; and the grosser parts are not dissolved, but follow the motion of the spirit, which as it were inflates and thrusts them out into various figures ; whence proceeds that saine generation and organization. Vivification therefore always takes place in a matter tenacious and viscous, but at the same time soft and yielding, that there may be at once both a detention of the spirit, and a gentle yielding of the parts, as the spirit moulds them. And this appears in the matter of all things, as well vege

, table as animal, whether generated from putrefaction or from seed; for there is manifest in them all a matter hard to break through, but easy to yield.

RULE IV. In all animate bodies there are two kinds of spiritsu; lifeless spirits, such as are in bodies inanimate, and in addition to them a living spirit.

EXPLANATION.

I have already observed that to procure long life the human body should be considered first as a body inanimate and unsupported by aliment; and secondly as a body animate and nourished; for the first consideration gives laws touching consumption, the second laws touching repair. We should know therefore that there are diffused in the substance of every part of the human body, as the flesh, bones, membranes, organs and the like, during lifetime, spirits of the same kind as those which exist in the same things, flesh, bones, membranes and the rest, when separated and dead; such likewise as remain in the corpse. But the living spirit, though it governs them and has some agreement with them, is very different from them, being integral and self-subsisting. But between the lifeless and vital spirits there are two special differences; the one, that the lifeless spirits are not continued in themselves, but are as it were cut off and surrounded by the grosser body which intercepts them; as air is mixed up in snow or froth. But all the vital, spirit is continued in itself, by certain channels through which it passes, without being totally intercepted. And this spirit likewise is of two kinds; the one merely branched, and permeating through small thread-like channels; the other having a cell likewise, so that it is not only continued in itself, but also collected in a considerable quantity, according to the proportion of the body, in some hollow space; and in this cell is the fountain of the streamlets which diverge from thence. This cell is chiefly in the ventricles of the brain, which in the lower animals are narrow; so that the spirits seem rather to be diffused over the body than seated in cells; as may be seen in serpents, eels and flies, the different parts whereof continue to move long after they are cut in pieces. So likewise birds quiver for some time after their heads are cut off, because they have small heads, with small cells; but the nobler animals, and men most of all, have larger ventricles. The other difference between the spirits is, that the vital spirit has in it a degree of inflammation, and is like a breath compounded of flame and air, as the juices of animals contain both oil and water. But this inflammation supplies peculiar motions and faculties; for inflammable smoke even before it catches fire is hot, rare, and movable, and yet it is a different thing after it has become flame. But the inflammation of the vital spirits is gentler by many

degrees than the softest flame, whether of spirit of wine or other; and besides, it is largely mixed with an aerial substance, so as to be a mysterious combination of a flammeous and aerial nature.

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RULE V. The natural actions are proper to the several parts. but they are excited and sharpened by the vital spirit.

EXPLANATION.

The actions or functions of the individual members follow the nature of the members themselves; as attraction, retention, digestion, assimilation, separation, excretion, perspiration, and even the sense itself, depend upon the properties of the several organs, as the stomach, liver, heart, spleen, gall, brain, eye, ear, and the rest. But yet none of these actions would ever be set in motion without the vigour, presence, and heat of the vital spirit; as iron could not attract iron, unless it were excited by the magnet; and an egg could not be productive, unless the substance of the hen had been actuated by the treading of the cock.

RULE VI. The lifeless spirits are nearly of the same substance as the air ; the vital spirits more akin to the substance of flame.

EXPLANATION. The explanation of the foregoing 4th rule is also a declaration of this; but further, it is the reason why all fat and oily substances continue to exist long in their natural state ; for neither does the air prey much upon them, nor have they much desire to unite with the air. But the idea that flame is lighted air is a vain conceit, seeing that flame and air are no less heterogeneous than oil and water. When therefore this rule declares that the vital spirits approach nearer to the substance of flame, it must only be understood that they do this more than the lifeless spirits, and not that they pertain more to the nature of flame than of air.

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