134 LECTUEE VI. 



ness, in the same manner ? Does he not knock down his 

 adversary by striking him in the breast with his head ? and do 

 not two Negroes, when fighting, butt one another hke con- 

 tending rams ? We cannot, therefore, accept the exceptional 

 state of man in this respect, nor the inference drawn from it, 

 though it has been assumed by ancient authors. The older 

 the opinion, the older is the error. 



There is, however, an exceptional condition, an essential at- 

 tribute of human nature, and one which distinguishes the 

 bimana from all other mammals, namely, the upright posture. 

 The main characters of the human structure are in harmony 

 with this position ; they partly stand to each other in the rela- 

 tion of cause and effect. It is true that an upright posture 

 cannot be said to be entirely confined to man to the exclusion 

 of the rest of the animal kingdom ; for among birds there are 

 some, as the penguin and the auk, which stand and walk as 

 uprightly as man. Here, however, there are other structural 

 relations which occasion this posture. Man is absolutely dis- 

 tinguished from the animals most closely related to him struc- 

 turally, the apes, by the^ erect posture, which is only_ assumed 

 by the latter transiently, or in consequence of training. 



The proportionally large skull, with its contents, rests in 

 equilibrio on the points of support afforded by the vertebral 

 column. The arrangement exhibited by the articulating sur- 

 faces of the so-called atlas, and of the second cervical vertebra, 

 the axis, almost seems to have been the model for such mecha- 

 nical contrivances as are used to secure the horizontal position 

 of the mariner's compass or of ship lamps. Two articular 

 surfaces on the upper side of a ring, i. e., the first cervical 

 vertebra, the atlas, as anatomists call it, — transverse articular 

 surfaces on the under side of the same ring, — a projection 

 serving as an axis on which the ring turns — the head is 

 balanced on this mechanism, and has its motions free in all 

 directions. The muscles, tendons, and hgaments are so at- 

 tached, that the slightest effort is sufficient for the re-establish- 

 ment of the disturbed equilibrium. When we find in the 

 animal world a heavy head on the top of the spinal column, we 

 also find a development of the spinous processes of the cervical 



