6gO PHILOSOPHICAL TRANSACTIONS. [aNNO 1743. 



very seldom able to trace them into its substance, because they terminate ab- 

 ruptly at the edge of the cartilage, like the vessels on the albuginea oculi when 

 they come to the cornea. The larger vessels, which compose the vascular 

 circle, plunge in by a great number of small holes, and disperse themselves into 

 branches between the cartilage and bone. From these again there arises a crop 

 of small short twigs, that shoot towards the outer surface ; and whether they 

 serve for nourishing only, or if they pour out a dewy fluid, Mr. H. does not 

 pretend to determine. However that be, he observes that the distribution 

 of the blood-vessels to the articulating cartilages is very peculiar, and seems cal- 

 culated for obviating great inconveniencies. Had they run on the outer sur- 

 face, the pressure and motion of the two cartilages must infallibly have occa- 

 sioned frequent obstructions, inflammations, &c, which would soon have ren- 

 dered our motions painful, and at last entirely deprived us of them. 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 such 

 accidents. 



It were to be wished we could trace the nerves of cartilages : but, in relation 

 to these organs, here, as in many other parts of the body, we are under a ne- 

 cessity, from the imperfection of our senses, of being satisfied with mere con- 

 jecture. And though, from the great insensibility of a cartilage, some have 

 doubted of its being furnished with nerves ; yet, as it is generally allowed that 

 these area sine qua non in the growth and nourishment of animals, we have no 

 sufficient reason to deny their existence in this particular part. With regard to 

 the manner of their distribution, we may presume, from analogy, that they fol- 

 low the same course with the blood-vessels. 



The articulating cartilages are most happily contrived to all purposes of mo- 

 tion in those parts. By their uniform surface, they move upon one another 

 with ease : by their soft, smooth, and slippery surface, mutual abrasion is pre- 

 vented : by their flexibility, the contiguous surfaces are constantly adapted 

 to each other, and the friction diffused equally over the whole : by their elas- 

 ticity, the violence of any shock, which may happen in running, jumping, &c. 

 is broken and gradually spent : which must have been extremely pernicious, if 

 the hard surfaces of bones had been immediately contiguous. As the course of 

 the cartilaginous fibres appears calculated chiefly for this last advantage, to 

 illustrate it, we need only reflect on the soft undulatory motion of coaches, 

 which mechanics want to procure by springs ; or on the difference between 

 riding a chamber horse and a real one. To conclude, the insensibility of arti- 

 culating cartilages is wisely contrived, as by this means the necessary motions 

 of the body are performed without pain. 



If we consult the standard chirurgical writers, from Hippocrates down to the 



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