136 



we are astonished at the small proportion, which it bears to the 

 cavity containing the brain. The predominance of the cranium, 

 compared with the other cavities of the head, and with the entire 

 skeleton, (though gradually diminishing, from almost tlie first mo- 

 ment of formation,) is preserved, to a certain extent, till the com- 

 pletion of growth. Not merely till the cranium has ceased to' grow; 

 but, till all the other parts of the skeleton have acquired their per- 

 manent dimensions. 



From observations I have made, I am convinced, that the cavity 

 of the cranium has arrived at its permanent dimensions, at the 

 eighth year of our existence, or perhaps sooner. To general observers, 

 this remark would not appear correct. Their attention is, however, 

 only directed to the exterior of the cranium ; and, it must be ad- 

 mitted, that, after this period, the cranium, viewed externally, in- 

 creases in its dimensions ; but this increase of external dimension 

 has no influence on the cavity. It is produced by an increase of 

 the thickness of the bones of the cranium and their coverings. This 

 fact is confirmed by the observations of the Wenzels ; * these ac- 

 curate and indefatigable anatomists having observed, that the brain, 

 which is contained in, and fills this cavity, has attained its perma- 

 nent dimensions at the age of seven years. As therefore the cavity 

 of the cranium has arrived at its maximum, between the seventli 

 and eighth year, (a period much earlier than any other part of the 

 skeleton,) it follows, that the permanent relations of magnitude are 

 not established, when the cranium ceases to grow; but at the con- 

 clusion only of the development of the entire skeleton. 



The ca\ ity of the cranium does not increase, in the same ratio, 



• Wenzel, (Joseph and Cliarles,) de Penitiori Structura Cerebri Hominis et Brutorum. 

 Fol. Tubingen, 1812, p. 254, 295. 



