277 



face of the dura mater, a fibrous membrane which serves as a periosteum 

 to the bones it lines*. 



CXLII1. Of the size of the brain. Of all animals, man has the most 

 capacious skull, in proportion to his face, and, as the bulk of the brain 

 is always of a size t proportioned to that of the osseous case which con- 

 tains it, the brain is also most bulky in man. This difference of size be- 

 tween the cranium and face, may be taken as the measure of the human 

 understanding and of the instinct of the lower animals ; the stupidity and 

 ferocity of the latter are greater, according as the proportions of these 

 two parts of their skull, vary from those of the human head. 



To express this difference of size, Camper imagined a vertical line 

 drawn from the forehead to the chin, and perpendicular to another drawn 

 in the direction of the base of the skull. He has called the first of these 

 lines facia!, the second, palatine or mental. It is easy to understand, that, 

 as the projection of the forehead is determined by the size of the skull, 

 the larger it is, the more the angle at which the facial line meets that 

 from the base of the skull must be obtuse. In a well-formed European 

 head, the facial line meets the palatine at an angle nearly straight, (of 

 between eighty and ninety degrees.) When the angle is quite straight, 

 and the line which measures the height of the face is completely vertical, 

 the head is of the most beautiful form possible, it approaches most to 

 that conventional degree of perfection which is termed ideal beauty. If 

 the facial line slopes backward, it forms with the palatine line, an an- 

 gle more or less acute, and projecting forward, the inclination increases, 

 and the sinus of the angle is shorter; if, from man, we pass to monkeys, 

 then to quadrupeds, to birds, reptiles, and fishes, we find this line slope 

 more and more, and, at last, become almost parallel to the mental, as in 

 reptiles and in fishes, with flat heads. If, on the contrary, we ascend 

 from man to the gods, whose images have been transmitted to us by the 

 ancients, we find the facial line to incline in a different direction, the an- 

 gle then enlarges and becomes more or less obtuse. From this inclina- 

 tion forward of the facial line, there results an air of grandeur and ma- 

 jesty, a projecting forehead, indicating a voluminous brain and a divine 

 intellect}. 



To obtain with precision, by this means, the respective dimensions of 

 the skull and face, one must measure, not only the outside, but, likewise, 

 draw the tangents on the internal surfaces, after dividing the head verti- 

 cally. There are, in fact, animals, in which the sinuses of the frontal 

 bone are so large, that a considerable portion of the parietes of the 



* Analagous to the serous membranes which line the cavities of the body, the arach- 

 noid is a shut sac, whose internal surface is every where in contact with itself, while its 

 external surface adheres to the two other meninges. The serosity which exudes from 

 the internal surface of the arachnoid differs from that which escapes from the other 

 serous membranes, owing to the almost entire absence of albumen from the former. 

 The exhalation that takes place from this membrane appears to be the source of a more 

 limpid and dilute effusion, even in disease, than that which is observed in the other 

 serous cavities. Copland. 



J- This should be ruialin'ed. In many animals the cavity of the skull is small, while 

 the osseous case appears large ; this great extent of bone is for the origin of the power- 

 ful muscles necessary to the seizing and comminution of their food. Godman. 



$ It should not be forgotten, that this is true only when the tbcial angle does not much 

 exceed 90 P . Foreheads projecting more than this, are most frequently those of idiots 

 or hydrocephalic persons. Godman. 



