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dr. j. cleland ox the variations of the human skull. 
Cretins and Idiots . — The Cretin form of skull described by Virchow has been already 
referred to in treating of the relation of the face to the cranium (p. 153). Reverting 
again to Virchow’s figures of the skull of the Cretin aged fifty-three, and of the new-born 
Cretin’s skull, there seems little difficulty, after all that has been said, in determining the 
nature of the cranial degeneration, and accounting for the appearance of prognathism 
which led Virchow to expect a projection of the face from underneath the cranium. 
The line of attachment of the tentorium, instead of beginning at a considerably lower 
level than the floor of the anterior fossa of the skull, and passing directly backwards, 
begins on a level with that part, and appears to rise as it passes backwards ; so that, 
instead of there being increased curvature to make up for shortness of base, as Virchow 
supposed, there seems to be a marked deficiency in cerebral curvature, and, as it were, 
a thick slice taken off the lower part of the middle and posterior lobes. This deficiency 
of curvature does not show itself in the skull by decrease of the angle between the plane 
of the foramen magnum and the floor of the anterior cranial fossa ; but although that 
angle is the index which we have been using as the measure of curvature, it in this 
instance misleads in consequence of a drawing up of the front of the foramen magnum, 
which is not the result of curvature, but of the mere shortness of the basilar process 
from synostosis, and the crushing up of the dorsum sellte to the level of the anterior 
cranial fossa. The want of development backwards of the cerebral hemispheres, 
indicated by the line of attachment of the tentorium in Virchow’s drawings, must, 
according to the principle of balance, have led to a great tilting backwards of the skull 
during life, and consequent projection of the jaws. The crushing up of the dorsum 
sellse, in these Cretins, to the level of the anterior cranial fossa, is a phenomenon not unlike 
what has occurred in skull 91 (Professor Thomson’s “ baker’s skull”), only that in that 
instance the basilar process has become more horizontal as it has been pushed up, while 
in the Cretin skulls it has not been so ; but in the Cretins, as well as in the “ baker’s 
skull,” there is the appearance of deformity by gravitation. Probably, as happens in the 
bones of rachitic skeletons, they had first yielded too freely, and then ossified too rapidly; 
nor is the circumstance that one of the skulls is that of a new-born infant adverse to 
this theory, seeing that in liter o the whole body presses down on the head. 
In the skull of the Idiot, 94, there is a totally different state of matters, probably a 
typical idiot form. Evidently the idiot’s skull figured by Carus* is of the same descrip- 
tion, although still more degenerated. Here there is no defect in the development of 
the base, no evidence of gravitation changes. The foramino-optic line and orbital length 
are both long, the base is steep, the cranial curvature great, the face largely developed, 
and, in connexion with this, there is a frontal sinus projecting far forwards in front of the 
brain. The base and face have gone through all the stages of a complete and full deve- 
lopment ; the vault alone is diminished, and that diminution is in height as well as 
breadth. The deficiency of height is best illustrated by the shortness of the frontal 
depth ; the deficiency of breadth is such that, as already mentioned, the greatest width 
* C. G. Cabtjs, Neuer Atlas der Cranioscopie, taf. xix. 
