344 



USE OF THE SUTURES. 



purtied afunder by the growtii of the brain, left that orgsm 

 fliould be cramped in its growth, in confequence of the com- 

 paratively flow growth of the bones of the Ikull. 

 Other fuppofed Other ufes attributed to the futures are merely flight ad- 

 vantages derived from their flruclure, which are enjoyed \n 

 early infancy, or till adult life, but gradually ceafe after that 

 period. Thus at the time of birth the loofe union of the 

 bones of the fliull accommodates the fliape of the head to the 

 figure of the different parts of the cavity through which il 

 pafles. At adult age, when the futures are fully formed, they, 

 may occafionally check the progrefs (if I may be allowed the 

 expreflion) of a fracture nearly fpent ; — or vibrations, com- 

 municated to the bones of the fltull, will be propagated with 

 lefs force (o the brain, in confequence of the bones being 

 leparated at the futures. It is, however, abundantly evident,^ 

 that thefe are not the main purpofes for which the futures are 

 formed j otherwife they w^ould not begin to be obliterated at 

 a period of life when they would perform thefe ofKces more 

 ufefully than ever. Confiflent with this remark we fliall find, 

 that the true purpofe for which they are formed, and the par- 

 ticular procefs with which they are conne6led, is fully com- 

 pleted before their obliteration takes place. 

 The cartilage When we take a view of the mode of jun61ion between 



deftlned to° b" ^^^^y bones, and parts of bones in the human body, which do 

 united, difap- not admit of motion, we find that with little exception they 

 pears at laft. ^jj ^g^gg jjj jj^jg particular ; that fooner or later the cartilage 

 or periofleum which once was interpofed is obliterated, and 

 thefe different portions, or entire bones, coalefce. 

 Intlances in the ^^j^g feparate portions, which originally compofe the 

 ribs and other "^ , • , . . ,- i r , /• i r 



bones. vertebrse, are early in thus uniting : after thefe the fides ot 



the lower jaw ; at a later period the epiphyfis of a cylindrical 



bone is united to its body : and flill later the bones of the 



fkuil ufually coalefce, and the futures are obliterated. Other 



bones, as thofe of the face, which have no motion and 



fuftain little weight, are irregular in this refpefl ; fometimes 



uniting, but generally remaining difiind, to the end of a long 



life. 



Manner in The original formation of the ofTeous fyfiem in feveral 



which the diflin6l pieces, refpeds principally its fpeedy ofllfication at 



offeous fyftem , ^ . , ,,.„ , ., r - . . r 



is completed, an early period or lite, and its future convenient extenhon, 



*«• till it has arrived at its full growth ; and we may coiifider it as 



5 a general 



