Above the body rises the neck, which is either firm or flexible at  pleasure. Must a man bear a heavy burden on his head?  This neck  becomes as stiff as if it were made up of one single bone.  Has he a  mind to bow or turn his head?  The neck bends every way as if all its  bones were disjointed.  This neck, a little raised above the shoulders,  bears up with ease the head, which over-rules and governs the whole  body. If it were less big it would bear no proportion with the rest of  the machine; and if it were bigger it would not only be disproportioned  and deformed, but, besides, its weight would both crush the neck and  put man in danger of falling on the side it should lean a little too  much.  This head, fortified on all sides by very thick and very hard  bones in order the better to preserve the precious treasure it  encloses, is jointed with the vertebræ of the neck, and has a very  quick communication with all the other parts of the body.  It contains  the brain, whose moist, soft, and spongy substance is made up of tender  filaments or threads woven together; this is the centre of all the  wonders we shall speak of afterwards.  The skull is regularly  perforated, or bored, with exact proportion, and symmetry, for, the two  eyes, the two ears, the mouth, and the nostrils.  There are nerves  destined for sensations, that exercise and play in most of those  pipes.  The nose, which has no nerves for its sensation, has a  cribriform, or spongy bone, to let odours pass on to the brain.  Amongst the organs of these sensations the chief are double, to  preserve to one side what the other might happen to be defective in by  any accident. These two organs of the same sensation are symmetrically  placed either on the forepart or on the sides, that man may use them  with more ease to the right or to the left or right against him--that  is to say, towards the places his joints direct his steps and all his  actions. Besides, the flexibility of the neck makes all those organs  turn in an instant which way soever he pleases.  All the hinder part of  the head, which is the least able to defend itself, is therefore the  thickest.  It is adorned with hair which at the same time serves to  fortify the head against the injuries of the air; and, on the other  hand, the hair likewise adorns the fore part of the head and renders  the face more graceful.  The face is the fore part of the head, wherein  the principal sensations meet and centre with an order and proportion  that render it very beautiful unless some accident or other happen to  alter and impair so regular a piece of work.  The two eyes are equal,  being placed about the middle, on the two sides of the head, that they  may, without trouble, discover afar off both on the right and left all  strange objects, and that they may commodiously watch for the safety of  all the parts of the body.  The exact symmetry with which they are  placed is the ornament of the face; and He that made them has kindled  in them I know not what celestial flame, the like of which all the rest  of nature does not afford.  These eyes are a sort of looking-glasses,  wherein all the objects of the whole world are painted by turns and  without confusion in the bottom of the retina that the thinking part of  man may see them in those looking-glasses.  But though we perceive all  objects by a double organ, yet we never see the objects double, because  the two nerves that are subservient to sight in our eyes are but two  branches that unite in one pipe, as the two glasses of a pair of  spectacles unite in the upper part that joins them together.  The two  eyes are adorned with two equal eyebrows, and, that they may open and  close, they are wrapped up with lids edged with hair that defend so  delicate a part.