An elementary treatise on human physiology : on the basis of the Précis élémentaire de physiologie / par F. Magendie.

  • Magendie, François, 1783-1855.
Date:
1844
Catalogue details

Licence: Public Domain Mark

Credit: An elementary treatise on human physiology : on the basis of the Précis élémentaire de physiologie / par F. Magendie. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    CHARACTERISTICS OF MAN. fers widely in this respect from the narrow, keel-shaped thorax of quadrupeds. Head. In the Head are lodged numerous important organs, developed in various degrees in different animals, which necessarily leads to great variety in the form of this part. It is the seat of the en- cephalon, the great controlling power of the body ; of the organs of the senses, and is intimately connected with deglutition and respiration, the chief organs by which animals are related to ex- ternal objects. From the nature of these organs, it is obvious that they must be variously developed, and that their dimensions, form, weight, and arrangement must necessarily vary in differ- ent animals, according to their destined attitude and habits. The predominant character of man is intellectuality, while his senses are subordinate to this function more than other animals. The encephalon or cranial portion of the head is therefore devel- oped in him in a corresponding degree. The prominent charac- teristics of other animals, on the other hand, are much more inti- mately connected with one or more of the other organs, the intel- lectual functions being altogether subordinate. These circum- stances, with their natural attitudes, thus furnish a key to the pe- culiarities observed in the head of man when compared with other animals. The head is obviously divisible into those parts occupied by the organs of the senses, or the face, and the enceph- alon. One of the most remarkable circumstances observed in contrasting the head of man with other animals is his large cra- nium and small face. It will be found generally true in all an- imals, in the outline presented by a vertical section of the head in the antero-posterior direction, that, as the proportion of the cranium exceeds that of the face, the intelligence increases, and vice versa. This rule holds generally good, not only as regards different animals, but the various tribes of men. Camper pro- posed what he called the facial angle as a simple, and, generally, accurate method of expressing these proportions. Supposing the skull to be viewed in profile, and a line drawn from the greatest projection of the forehead to that of the upper maxillary bone, this may be called the facial line. If a second line be drawn from the meatus auditorius externus along the floor of the nasal fossa?, so as to follow the direction of the base of the cranium until it touches the first line, the angle thus formed will be the facial angle of Cam- per. It is evident that this angle will increase as the anterior portion of the cranium becomes developed and the face smaller, and the reverse as the face is more prominent and the forehead retreating. This angle is about 80° in the Caucasian race ; about 70° in the negro; while in the different varieties of monkevs it varies from 60° to 30°. y The following figure represents an outline of the skull of the negro, with the lines which form the facial angle of Camper.