J9 



chcs between the cartilage and bone. From these 

 again there arise many short, but small twigs, which 

 shoot toward the outward surface. This distribu- 

 tion of the blood-vessels is very peculiar, and calculat- 

 ed for obviating great inconveniencies. Had they ruri 

 on the outward surface, the pressure and motion of 

 the two cartilages must have occasioned frequent ob- 

 structions and inflammations. But by creeping round 

 the cartilaginous brim, where there is little friction, 

 or under the cartilage, where there is none, they are 

 perfectly well defended from all such accidents. 



Cartilages are admirably contrived for all the pur- 

 poses of motion. By their uniform surface they move 

 one upon another with ease: by their soft, smooth 

 and slippery surface, mutual abrasion is prevented. 

 By their flexibility, the contiguous surfaces are con- 

 stantly adapted to each other. By their elasticity the 

 violence of any shock, which might happen in run- 

 ning, jumping, or the like, is broken, which must 

 have been extremely pernicious, if the hard surfaces of 

 bones had been immediately contiguous. The carti- 

 laginous fibres appear calculated chiefly for this last 

 advantage. To conclude, the insensibility of these 

 cartilages is no less wisely designed, that by this means 

 the necessary motions of the body may be performed 

 without paiu. 



6. The various parts of the body are cloathed with 

 Membranes, which are whitish tuniclos, extremely 

 thin and flexible, composed of fibres interwoven with 

 each other, as a piece of cloth is of threads. They are 

 fastened together by a kind of cartilages, which are 

 termed ligaments. 



7. An artery is a hollow canal, composed of fibres 

 closely twisted together, which conveys the blood 

 from the cavity of the heart to all the parts of the 

 body. All the arteries spring from two, the aorta or 

 great artery and the pulmonary artery. The latter 

 conveys the blood from the rig lit ventricle of the heart,' 



