40 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



by these two curves. It is important to bear in mind here that the 

 Holt curve is derived from 1,774 measurements, while our private- 

 school curve is based upon 886 measurements. Holt's values repre- 

 sent a city school, attended by children of a social status somewhat 

 better than average, who received better medical treatment and were 

 unquestionably living in better hygienic surroundings than the average 



Yrs. 2 4 6 8 10 12 14 76 18 20 

 FIG. 3. Relationship between body-weight and age with boys. 



child. Our private-school boys were likewise of a superior social 

 status, received better medical attention, and more especially indulged 

 in a considerable amount of active outdoor exercise, all of which factors 

 make for a distinctly heavier boy for a given age. One of the private 

 schools was an open-air school. The influence of outdoor life and 

 social environment is so striking here that we have continued our 

 curve for private-school children to the age of 18 years, at which 

 point our collection of data ends. 



While, therefore, our curve for laboratory boys is practically identi- 

 cal with that of Crum and Wood and measurably higher than the curves 

 of the foreign authorities, Quetelet and Schmid-Monnard, it is dis- 

 tinctly lower than the two curves for the private schools, which repre- 



