34 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



dealing with the physiology of normal youth. In the first place, our 

 own impressions of normality were substantiated by most careful 

 physical examinations, in which always one and frequently two physi- 

 cians passed critical judgment as to the normality of each child. Since 

 this last analysis, however, must depend upon the personal judgment 

 of the examiner, we have thought it would be highly desirable to check 

 up the results of the physical examinations, so far as possible, by com- 

 paring the cases passed upon as normal by the physicians with some 

 recognized standards which would be completely free from the personal 

 equation. To the uninitiated the personal impression made by a 

 child is always of great weight in estimating the state of normality, 

 and one instinctively says whether a child appears well-nourished or 

 undernourished. But age, height, and weight, as well as girths, 

 should be taken into consideration, and it is clear that personal im- 

 pressions may very likely err in estimations of this kind, and therefore 

 should be replaced, as far as possible, by accurately determined 

 measurements. Furthermore, it is clear that sexual differences appear 

 at an early age, so that boys and girls may not be classed together. 



At the completion of our experimental details, therefore, the selection 

 of normal material presented a great deal of difficulty. We were 

 instantly confronted with the question "What is normal?" While 

 we firmly believe that all obviously abnormal children were excluded, 

 it still remains an important point whether the general run of our 

 children measure up to the idea of normality held by many writers. 

 Heretofore the conception of normality has been in large part based 

 upon the average, and consequently the averages selected from a large 

 number of measurements of children of varying ages, weights, and 

 heights have been used to indicate the average or normal growth for 

 age, height, or weight of the child. This is not the place to define 

 what is normal and what is average, but this point will be taken up 

 in detail later on in this discussion. 



STANDARDS FOR DETERMINING THE NORMALITY OF CHILDREN. 



In considering the normality of children, special emphasis has 

 always been laid upon the relationship between body-weight and age 

 or between height and age, and only relatively recently between height 

 and body-weight, irrespective of age. The age factor has always been 

 the most important and the ratios of height to given age and body- 

 weight to given age still remain the most commonly used criteria. 

 At first sight this method of comparison would appear to be a relatively 

 satisfactory one. The measurements of body-weight and of height 

 are apparently very simple, and yet both are subject to considerable 

 errors, particularly in the case of boys. 



Weight of clothing. For .many obvious reasons, the weight of 

 children above 5 years of age is almost invariably given with clothing. 



