Anthropological Measurements of Cliildren. 29 



to height is of great importance to health, life insurance 

 companies declining to receive ai)plicants whose weight falls 

 much below the standard weight of their height. For these 

 reasons height should be preferred as the basis of the system. 



The question whether any given deviation is normal or 

 abnormal is answered by this system in two ways : in respect 

 of lieight, by the degree of deviation from the mean or norm 

 of the whole number of observations; in respect of other 

 dimensions, by the degree of deviation of the weight, girth 

 of cliest, etc. from the mean weight or girth of chest corre- 

 sponding to the height of the individual under examination, 

 this normal weight, etc. being determined with sufficient 

 exactness by taking the means and probable deviations of the 

 group in which the height falls. It is evident that all cases 

 included within 31 ±d must be termed normal, for the 

 chances are even that any individual measurement in a series 

 will fall within M±.d^ and are against its exceeding these 

 limits, being 4.64 against 1 that it will fall at 31 ± 2 d. 



Strictly speaking, all abnormal deviations in any dimension 

 are probably unhealthful, yet an important difference exists 

 in this respect between abnormal deviations in height and 

 abnormal deviations in weiglit, girth of chest, etc. as related 

 to height. It cannot be doubted that abnormal height is 

 probably (using the word in its teclniical sense) a disadvan- 

 tage. The potential energy of the body is converted into 

 mechanical labor and heat, by far tlie greater expenditure 

 taking the latter form. In the adult the total expenditure 

 in the form of heat is about 2700 calories in 24 hours (Helm- 

 holtz), of which 80.1 per cent escape in radiation, conduction, 

 and evaporation from the skin. Thus the superficies of the 

 body plays a great part in the dissipation of energy. The 

 superficies is greater usually in tall children than in short, a 

 difference of special imi)ortance in the young, in whom meta- 

 bolism is much more active than in the adult. More heat is 

 therefore lost by the abnormally tall than by those of normal 

 height. There is a disadvantage also in the loss by median- 



