Page:Popular Science Monthly Volume 63.djvu/393

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in the same person, and it may be attended by trickery on the part of the person measured. By the Metropolitan police a margin for error of two inches in each direction is allowed in classifying cases by height. Even with the greater accuracy of the French measurement a considerable margin has to be given. The accurate description of the color of the eye is still more difficult. The seven colors taken by M. Bertillon can be discriminated only by persons having much practical experience, and even then many doubtful and transitional cases must occur.

For the 'primary classification' that based on the first five Bertillon measurements, a complete outfit, such as would be necessary at an important registration station, would consist of 343 drawers, corresponding to the 5th power of 3, the number of possibilities involved.

The arrangement of this index register will be the same as M. Bertillon's, a cabinet of drawers first divided vertically into three divisions according to length of head, and horizontally according to width of head. The nine sections thus formed will be divided vertically according to length of finger and horizontally according to length of forearm, and again vertically according to length of foot. There will be 243 drawers, each containing one class of cards. The figures which are to determine the 'long,' 'medium 'and 'short 'of the several classes might be borrowed in the first instance from M. Bertillon, but in that case on account of racial differences they would have ultimately to be altered in order to keep the classes equal in size. It would be best, therefore, that the measurements taken in this country by Mr. Galton and by the Anthropological Institute should be utilized and correct figures for England fixed from the outset.

The above quotation from the English report is given in full mainly for the purpose of showing the great disadvantage to the entire system, which results from racial differences in bodily proportions, a fact which will necessitate either one of two alternatives, both bad; that of using special figures for each country or of having very unequal subdivisions in certain cases. This is a decided barrier to the internationalizing of the system and must necessarily be reckoned as a serious defect.

Without meaning to seem ungracious to a system the advantage of which over all previous methods has been universally recognized, and one the scientific principles of which reflect so much credit upon the deviser, it may be well, in closing this brief account, to enumerate the defects of the Bertillon system, some of which are, indeed, incident to any system which human ingenuity can devise, and the most of which have been foreseen, acknowledged and corrected so far as possible by M. Bertillon himself.

 1. The limitation of the system to the period of adult life.

2. The necessary disparities between the same measurements taken at different times by different mensurators, or indeed by the same one (percentage of error).

3. For the purpose of an equal classification, the necessity of assigning independent limits to the records kept by each nation.

4. The greater amount of time consumed in making a set of