(322 
raent^ may nevertheless occasion a moral perversion of the 
faenlties. 
Pardon so long a digression. 
II. A second class of deformations of the cranium 
are pathological. I have named them Plastic Deformations. 
My attention was first directed to them about 10 years 
ago. These exhibit a change of form in the skull from 
the weight of the brain itself, or of burdens borne on the 
head, by reason of a loss of consistency in the cranial 
bones. Excessive thinness of the bones, atrophy from 
disease or age, and softening of the osseous texture, are 
the causes of plastic deformities of the skull. They chiefly 
show themselves by a bulging out of the circimiference of 
the cranium, platy-cephalism and an apparent elevation of 
the basal portions surrounding the occipital foramen. These 
latter are supported on the vertebral column and cannot 
be elevated into the cranial cavity, or undergo other change 
of position. Hence, it is the upper and lateral portions 
of the skull which are really depressed. 
This kind of deformation is not common, but some- 
times proceeds to an extent much greater than would 
have been expected *). 
III. The next class of deformations, are the Artificial 
Defariiiaticiis. 
These require to be divided into two orders, a. Those 
which are induced intentionally, or by design, h. Those 
which are accidental, or unintentional. 
a. The almost inconceivable and very varied fantasti- 
cal shapes given to the head in infancy, purposely, by 
*) See: Sur les Deforinations plastiques du crane par D:r J. Barnart) Davis 
Mem. de la Soc. d’Anthropologie. I. 379. 
