14 SURGICAL APPLIED. ANATOMY. [Chap. n. 



tissue so reduced that the affected district feels 

 to the finger as if occupied by parchment, or> as 

 some suggest, by cartridge paper. It is, on the other 

 hand, about, the site of the anterior fontanelle that 

 certain osseous deposits are met with on the surface 

 of the skull in some cases of hereditary syphilis 

 (Parrot). These deposits appear as rounded elevations 

 of porous bone situated upon the frontal and parietal 

 bones, where they meet in the middle line. These 

 bosses are separated by a crucial depression repre- 

 sented by the frontal and sagittal sutures on the 

 one hand, and the coronal suture on the other. They 

 have been termed " natiform " elevations by M. 

 Parrot, from their supposed resemblance, when viewed 

 collectively, to the nates. To the English mind they 

 would rather suggest the outlines of a "hot-cross 

 bun." 



It is necessary to refer to the development of 

 tlie skull in order to render intelligible certain con- 

 ditions (for the most part those of congenital mal- 

 formation) that are not unfrequently met with. 

 Speaking generally, it may be said that the base of 

 the skull is developed in cartilage, and the vault in 

 membrane. The parts actually formed in membrane are 

 represented in the completed skull by the frontal 

 and parietal bones, the squamo-zygomatic part of the 

 temporal bone, and the greater part of the expanded 

 portion of the occipital bone. The distinction between 

 these two parts of the skull is often rendered very 

 marked by disease. Thus there are, in the museum 

 of the Royal College of Surgeons, the skulls of some 

 young lions' that were born m a menagerie, and that, 

 in consequence of mal-nutrition, developed certain 

 changes in their bones. A great part of each of these 

 skulls shows considerable thickening, the bone being 

 converted into a" porous structure ; and it is remark- 

 able to note that these changes are limited to such 



