144 ALE§ HRDLlfiKA 



Individual Teeth. — Valid measurements can be secured only on teeth 

 that are normal and unworn (or worn only so that the dimensions we 

 want to measure are not affected). 



Incisors: Main measurements — The total length of the tooth, and 

 the greatest breadth of the crown (at right angles to the long axis of 

 the tooth). Additional measurements are the maximum antero- 

 posterior diameter of the crown (at its base), the minimum breadth of 

 the crown (also at its base), and the height of the crown (in median 

 line on the labial surface). 



Canines: Principal measurements — Total length, and height of 

 crown (in median line, labial surface). A useful measurement is that 

 of the total displacement of the tooth, in glycerine, oil or other liquid, 

 in a graduated small jar or tube. 



Premolars and molars: Essential measurements — Maximum height 

 (with axis of the tooth vertical) ; length and breadth. The length and 

 breadth measurements of these teeth are not as easy to make as might 

 at first appear, which is particularly true of the anterior premolar in 

 some of the lower forms of mammals. The most satisfactory rule is 

 to measure the length along the median antero-posterior axis of the 

 tooth as it lies or lay in the jaw; and the breadth at right angles to 

 this axis. 



The above measurements on individual teeth are of value both 

 anthropologically and phylogenetically; but due to the care with which 

 they must be taken and the time involved in getting the specimens, 

 they should be reserved for special investigations. 



The teeth of man, even more than any of his other structures, call 

 for careful comparative work on Primates and lower mammals. 



Measurements of Brain 



Uniformity in brain measurements is equally as desirable as uni- 

 formity in the measurements of other parts of the body; but no at- 

 tempt has yet been made at their international definition and regula- 

 tion. Each author so far has followed his own inclinations, with the 

 result that outside of weight but little comparison of the measurements 

 is possible. 



The brain is not an easy organ to measure. Due to its softness, 

 from the moment it is exposed it tends to sag down more or less 

 according to the condition of the body and the temperature, and it 

 may readily be deformed if not given the best of care in preservation. 

 Yet measurements that could be used for comparison both within and 



