368 LAMARCK, HIS LIFE AND WORK 



during a limited time and with the aid of the con- 

 traction of several of his muscles. 



" If the vertebral column of the human body 

 should form the axis of this body, and sustain the 

 head in equilibrium, as also the other parts, the man 

 standing would be in a state of rest. But who does 

 not know that this is not so ; that the head is not 

 articulated at its centre of gravity; that the chest 

 and stomach, as also the viscera which these cavities 

 contain, weigh heavily almost entirely on the an- 

 terior part of the vertebral column ; that the latter 

 rests on an oblique base, etc. ? Also, as M. Richerand 

 observes, there is needed in standing a force active 

 and watching without ceasing to prevent the body 

 from falling over, the weight and disposition of parts 

 tending to make the body fall forward. 



" After having developed the considerations re- 

 garding the standing posture of man, the same 

 savant then expresses himself: ' The relative weight 

 of the head, of the thoracic and abdominal viscera, 

 tends therefore to throw it in front of the line, 

 according to which all the parts of the body bear 

 down on the ground sustaining it; a line which 

 should be exactly perpendicular to this ground in 

 order that the standing position may be perfect. The 

 following fact supports this assertion : I have ob- 

 served that infants with a large head, the stomach 

 protruding and the viscera loaded with fat, accustom 

 themselves with difficulty to stand up straight, and 

 it is not until the end of their second year that they 

 dare to surj^ender themselves to their proper forces; 

 they stand subject to frequent falls and have a nat- 

 ural tendency to revert to the quadrupedal state.' 

 {Physiologic, vol. ii., p. 268.) 



" This disposition of the parts which cause the 

 erect position of man, being a state of activity, and 

 consequently fatiguing, instead of being a state of 

 rest, would then betray in him an origin analogous 



