52 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



and their diet is woefully deficient in the "food-accessory substances," 

 they will have a reasonably normal skeletal growth with increasing 

 age. It is at this point that we note the special significance of the 

 time-honored early consideration of the relationship of height to age. 

 If the height is not up to that ordinarily found for the age, then we 

 may reasonably assume that the "food-accessory substances" in the 

 diet are deficient, unless we are dealing with an abnormal class of 

 individuals containing a large number of foreign population of normally 

 short stature. If the height is equal to that normally found for the 

 age but the weight is too low for the height, we may then look for a 

 deficiency in the caloric intake that is, the calories ingested are 

 not sufficient to take care of the heat output existing at the time, 

 and while food may be ample for normal exercise, with excessive 

 exercise there is deficiency in growth. Here we have the situation 

 which is so popularly expressed by the statement that the boy "runs 

 himself as thin as a rail." 



From the foregoing consideration of the several factors affecting 

 growth, it can be seen that a study of our growth-curves on the whole 

 that is, of our height-age, weight-age, and height-weight ratios is 

 probably involved by the question of nationality, the question of 

 environment and social status as reflected in the food, exercise, and 

 medical care, the question of "food-accessory substances" in the diet, 

 and the caloric intake. Some of these questions, certainly that of 

 nationality and medical care, are extremely difficult to consider 

 separately. From our curves, however, certain deductions may 

 legitimately be drawn. In the first place, we have seen that, based 

 on the relationship of height to age and weight to age, our laboratory 

 children as a whole, both boys and girls, measure up to the best and 

 most representative standard of American children, i. e., the data of 

 Crum and Wood, but that in neither of these relationships do they 

 measure up to the private-school children, either those studied by 

 Holt or by ourselves. It appears, therefore, that the private-school 

 children are taller and heavier for their age; but a subsequent con- 

 sideration of the relationship between height and weight shows that 

 on the whole they are a little thinner for the same height than are our 

 children. 



ANTHROPOMETRIC MEASUREMENTS AS INDICES OF GROWTH. 



From a careful consideration of the various relationships between 

 height, weight, and age we are convinced that the best ratio to indicate 

 the normal state of nutrition is that of height to weight. Still, in a 

 subject as important as this, it is desirable to make use of every 

 conceivable measurement that may possibly contribute towards clari- 

 fying the problem as to what is the normal state of nutrition. Many 

 writers have used, in addition to height and weight, typical measure- 



