ANTHROPOMETRY 43 



behaviour. The honest, friendly and able worker, with earnest, 

 dignified procedure, will have little difficulty in succeeding among 

 any class of people. 



Grouping hy Age. — This will be guided by precedence and what 

 may be called the scientific sense. It may differ somewhat according 

 to the number of available subjects. In series of ample size, the 

 segregation up to 6 weeks of age should be by weeks, from that on 

 up to 1 year, by months. From 1 and up to 33^ years, by half a year; 

 and thereafter by the year. The months and years are counted in 

 such a way that "6 months," for instance, will embrace everything 

 from 5 months and 16 days to 6 months and 15 days, while "6 years" 

 will include all subjects from 5}/^ to 63^ years.' The grouping of small 

 series of subjects is difficult, but the standard scheme should be fol- 

 lowed as far as practicable. In especially important small series 

 it is advisable to give the exact ages. The adopted system of 

 grouping must, of course, always be clearly outlined in the report on the 

 observations. 



It is safe to include young men from 20 and young women from 18 

 years onward among adults, provided these subjects are not repre- 

 sented disproportionately in the series examined. It would not be 

 proper, however, to take a class of such sub-adults, especially males, 

 as fully equivalent to the full-growns of the same racial or social 

 group, particularly in stature, chest, and few other measurements. 



In a similar way individuals from 60 to 70 years of age should not 

 be included in a general series if represented by a larger relative number 

 than that by which they are represented in the general population. 

 If more are available, they should be placed in a series of their own; 

 and this precaution should be invariably followed with those above 70. 

 The reason for separating the old is that various features and 

 proportions have altered and continue to alter to the end of their 

 life. These comprise the nose, ears, jaws, chest, stature and other 

 parts. The only dimensions that are not appreciably altered in 

 senility are those of the head, with the length of the limbs, hands and 

 feet, and pelvic dimensions. 



Estimation of Age. — So long as the student deals with Whites only, 

 there will be little difficulty about ascertaining the ages of his subjects; 

 but among more primitive peoples records of age are seldom kept and 

 the observer will have to take a recourse to estimates. The value of 



'This method is preferable to that which would include under the "6 years" 

 all subjects between 6 and 7. The mean of such a group would be 6^ years. 



