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base of the scull, are not as large, in proportion to the size of the 

 cranium, in early life, as afterwards ; but there is, at all times, the 

 same proportion between the magnitude of the foramina, for the 

 transmission of nerves and blood vessels, and that of the cavity of the 

 cranium : with this exception, however, that the hole, t'u'pugh 

 which the blood of the lateral sinus passes, is relatively smaller in 

 proportion to the youth of tlie subject. 



There occurs, at different periods, a very remarkable change in the 

 position of the large foramen of the occipital bone. The younger the 

 subject, the nearer this foramen, and consequently the condyles, for the 

 articulation of the occiput with the spine, to the centre of the base of 

 the cranium. There is probably a connexion between the situation of 

 this hole and the development of the face ; for, the greater the deve- 

 lopment of the face, the farther the foramen is removed backwards ; 

 and it is likely, that its place in the adult is determined by the quantity 

 of room required for the face and pharynx. Its situation however, in 

 early life, so much nearer the centre of the base than afterwards, must 

 be considered as, in some measure, ovi^ing to the greater rapidity of 

 the growth of the posterior than anterior parts of the cranium. What- 

 ever may be the cause, which determines this peculiarity, it serves 

 the useful purpose of rendering the head nr^ore easily supported by 

 the action of its muscles ; which are, in early life, but weak, com- 

 pared with the size of the cranium. 



The varieties of structure, which the cranium exhibits, at dif- 

 ferent periods of life, will be more fiilly considered, when speak- 

 ing of the changes of structure, which the whole skeleton under- 

 goes ; but, as some observations on this subject appear to be here 

 required, I shall make a few remarks, reserving the remainder for 

 a future occasion. 



The walls of the cranium, when this portion of the skeleton 



u2 



