This line elongates, and in time there may be observed, as a model somewhat more complete of the future animal, a division of this line by the rudiments of vertebrae. To speak correctly, this form is then the first canon of all the other organs of the future skeleton, for after the manner of its production and development should be regulated all the organism. There are extremely interesting relations when the ratios of the length of the free vertebral column are examined in the new-born child and in the adult. In the first (i.e. at the end of foetal life) it is found that the length of all the twenty-four free vertebrae - from the atlas to the last lumbal vertebra - correspond in a normal infant precisely to one-third of the same column of free vertebrae, consisting of twenty-four vertebrae, measured in the adult at the end of the epoch of growth by a line from the spine of the atlas to the spine of the last vertebra.'
The modulus, therefore, which he employed, and which he considered to be both physiologically and philosophically justified, was one-third of the length of the human spine. By applying this rule, then, it ought, in his opinion, to be possible to draw the various parts of the body with mathematical accuracy. 'His investigations,' says Sir George Humphry, 'conducted with all the assiduity and accuracy which characterize the German anatomists, appear to justify the selection, for he found the various parts of the frame to correspond in a remarkable manner with this standard. Thus the length of the skull from the forehead to the occiput equals one modula The height from the vertex to the lower margin of the upper jaw is the same. The circumference of the skull is three modules, or the whole length of the spine. The length of the breast-bone and of the shoulder-blade is in each case one module. The width of the chest from the extremity of one clavicle to that of the other is two modules. In the pelvis each of the measurements from the highest point of the ilium to the symphysis pubis, from the anterior superior spine to the tuber ischii, and from one anterior inferior spine to the other, corresponds with one module. The arm and fore-arm give three modules and the hand one.
The thigh-bone gives two and a half, the tibia two, and the foot, from the ankle to the tip of the toe, one. The height of the body is nine and a half modules. The module measures eighteen centimetres, or rather more than seven inches, making the entire figure five feet six and a half inches, or five feet seven inches. These,' he proceeds, 'are the ideal proportions of the well-developed European, deduced from the measurements of numerous skeletons. They represent the mean between the male and the female, and are stated by Carus to be generally true, though not applicable with mathematical accuracy to any one person, slight deviations from the standard being essential to the endless varieties of individual form. The measurements which I myself have made for the purpose of testing the value of this means of determining the scale of proportions of the figure, though in a general manner confirmative of the results obtamed by Carus, have proved that the exceptions to the rules laid down by him are very numerous.' It has been already mentioned that Carus caused to be constructed., according to directions drawn up by himself, a statuette or canonical figure, as he called it.
Of this he says: 'No sex has been assigned to this little statue, and it is easy to see that, in order to form a living individuality, the modulus or canon must always be made to vary slightly. For instance, if I wished to depict a woman's body I should give a little less breadth to the shoulders, and I should make some members more voluminous; while I should act exactly the contrary in the case of a man. In the same way the individualities might be varied: if I wished to represent a Cicero or a Leibnitz I should give to the head more than a module in height and length, and less at the extremities; on the other hand, if I wished to represent an athlete or a giant, I should add to the limbs, and should take ten modules or more as the height of the whole body.
By this means one could even succeed in depicting every sort of expression by an algebraical formula, where one would have the same elements, but increased or diminished in their value.' Mr. Roberts' criticism of the foregoing facts and figures is of so much interest that I shall here quote it. 'Thus,' he says,'it appears that Professor Carus uses his "canon" either as a kind of artist's lay-figure, which he dresses out according to his fancy, or as a skeleton, which he clothes with flesh according to his anatomical and physiological knowledge - knowledge, it must be remembered, which must be first obtained from actual observation and measurement of the living model. The canon may, indeed, be theoretically correct, but it can be of little practical use for scientific purposes. The greater breadth of shoulders required to convert the statue into the figure of a man must first be determined by actual measurement, as must also the greater breadth of pelvis to convert it into the form of a woman, before we can be satisfied that it represents the natural human form. The difficulty would be still greater if it were attempted to represent any decided deviation from the typical form.