258 ANIMAL MECHANICS. 



body was then pierced by steel " spits," placed in three axes at right 

 angles to each other. From these spits the body was in turn suspended, 

 and inasmuch as the centre of gravity must in each ease he in the 

 plane vertical to the axis of suspension, it could be readily fixed by 

 finding the point of intersection on these three planes. Having found 

 the centre of gravity for the whole body, the head and limbs were 

 removed from the trunk, and their centres of gravity determined by the 

 same method. 



In a typical subject, to which special reference is made, the centre of 

 gravity for the whole body was 4 - 5 cms. above the axis joining the centres 

 of the heads of the two femora, and on a level with the upper border of 

 the third sacral vertebra. The centre of gravity of the head was plumb 

 above the atlanto-occipital joint, and those of the limbs almost 

 exactly in the line joining the neighbouring joints ; thus, the centre of 

 gravity of the arm and thigh lay in the lines joining the centres of the 

 heads of the humerus and femur with the middle point of the axis of 

 the elbow- and ankle-joint. The centre of gravity of the torso lay in the 

 line joining the atlanto-occipital joint to the centre of the line joining 

 the centres of the humeral heads. 



The centres of gravity of the different portions of the body lying in the 

 lines joining the principal joints, it was possible to arrange a skeleton of a 

 subject similar in build to the frozen subject, so that the axes of all the 

 joints were in the same frontal plane. In this case, were the skeleton 

 clothed with flesh, the centres of gravity would fall in this plane. The 

 skeleton was photographed from the front and profile, and the centres of 

 gravity, the positions of which were calculated from the observations made 

 upon the frozen subject, were indicated, together with the joints on two co- 

 ordinate planes, one in a frontal and the other in a sagittal direction. These 

 planes were mapped out in equal squares of 1 mm., and the position of any 

 point, say the centre of gravity of a limb, could be indicated as a plus or 

 minus distance from the line of intersection of these planes in both a frontal 

 and in a sagittal direction, together with a distance along the line of 

 intersection. Thus the centre of gravity of the whole body falling in the 

 frontal plane would give the deviation along the sagittal plane ; those for 

 the head and trunk lying in the lines of intersection would show deviation 

 for both the frontal and sagittal plane, while the centres for the arms and 

 legs, lying as they do to the side, would give a deviation in the frontal plane 

 of ± x cms (see Fig. 122). 



The next step taken by Braune and Fischer was to utilise the services of a 

 soldier of nearly the same proportions as the cadaver used. The positions of 

 his joint-axes were indicated on the surface of the body, and he stood in 

 such a manner that these joint-axes plumbed one over the other; and, by 

 inference from the dead subject, his centre of gravity and those of his limbs 

 lay in the same frontal plane. This was termed the normal position (Normal- 

 stellung). A profile photograph was then obtained, on which was projected 

 a millimetre network of equal squares, from which plus and minus deviations 

 from the line of intersection of the frontal and sagittal planes could be 

 measured on the sagittal plane. When the soldier assumed the military 

 position (German), or a position of ease, the joints and centres of gravity 

 occupied new positions, moving forwards, or backwards, downwards or 

 upwards, on the sagittal plane. Photographs were taken of the soldier in 

 these new positions ; and the new positions of his centres of gravity of limbs, 

 trunk, head, etc., measured on the co-ordinate planes. From these data the 

 position of the centre of gravity of the whole body was calculated, by the 



