LECTURE II. 27 



sessing, also, flatter zygomatic arclies, and therefore narrower 

 faces, and perliaps also longer skulls.* It is clear, therefore, 

 that the advice, to avoid prominences and to select the thinnest 

 parts of the skull, should certainly be attended to in estimating 

 the internal capacity of the cranium ; whilst, on the other 

 hand, the development of lines and crests is of importance, 

 as affording indications for distinguishing races. For the ques- 

 tion may also be asked, has any given race strongly developed 

 temporal ridges because it is carnivorous ? or, is it carnivorous 

 because of the great development of these ridges and of the 

 muscles of mastication ? 



Still, it is very difficult practically to follow Von Baer's 

 well meant advice. The thinnest part of the cranium is just 

 the centre of the temple, which is covered by the temporal 

 muscle : but this point, though well known even in common 

 life from the danger attending a blow on this spot, can neither 

 in the living nor the dead subject be determined with that 

 accuracy requisite for measurements ; whilst those spots 

 nearest the skin generally correspond with the ridges and 

 muscular projections. The objection which may be made to 

 so many methods, viz., their inapphcabihty to both the 

 living and dead subject, applies also to the otherwise ra- 

 tional method lately proposed by Professor Busk of London. 

 This mode of measurement is based essentially upon a fixed 

 vertical Kne passing through the centre of the auditory open- 

 ing, and drawn from the vertex at the point where the 

 sagittal and coronal sutures meet. The selection of the ex- 

 ternal aperture of the ear as the starting-point of the radii 

 and angles is unobjectionable ; but the perpendicular hne can 

 hardly be determined with accuracy. In many skulls the exact 

 point can only be guessed at, as the sutures are frequently 

 denticulated to such an extent that the exact spot in which they 

 meet may be outside the central line, and consequently either 

 before or behind the point. It is, moreover, impossible 

 to find this point on the living head ; and as all other Hnes 

 depend upon the vertical, Busk^s method of measurement can- 



* This is a very ingenious theory, but must be pronounced, to be as yet 

 mere si^eculation. — Editor. 



