Hrdlicka. i 49 



instrument should always be held diagonally to the long axis of the 

 body. With care, measurements of this nature become quite accu- 

 rate and satisfactory. 



The results of the measuring, as will be seen from the appended 

 figures, show first of all the growth of the chest during the different 

 ages of the children. 



In the second place, the figures demonstrate the differences which 

 exist in the two proportions of the chest of the same height between 

 the males and the females and between the white and the colored 

 children. 



Finally, calculations were made of the relation of the antero- 

 posterior to the lateral diameter of the thorax at the different ages 

 of the subjects measured, and these proportions or thoracic indexes, 

 show the regular form of the chest, and the variations of this form, 

 in the different ages of the children. 



The size of the chest is greater on an average at all ages in the 

 male than it is in the female children. This is the case in both the 

 white and the colored subjects. When, however, we come to the 

 females above 1 1 years of age, where the development of the breasts 

 begins, the proportions of the chest will increase in the female and 

 may surpass those of the male of the same age. This increase in 

 depth of the female chest at or after puberty is due to additional 

 deposition of fat and not to any changes in the osseous thorax. 



In the colored children the chest is of very nearly the same size 

 in the boys, but is somewhat smaller in the girls, than it is in cor- 

 responding sexes of white children. In both the colored boys and 

 girls the chest is a little deeper than it is in the white children of 

 corresponding sexes and ages. This difference lies in the thoracic 

 cage itself. 



The chest index shows at least one very interesting feature. In 

 all classes of children the thorax is seen to be considerably deeper 

 in early childhood than it is later. The increase of flatness takes 

 place gradually and almost regularly through all the ages of the 

 children, so far as our records go, with the exception of the females 

 after the breast development takes place. The indices show very 

 well the somewhat deeper character of the chest in the negro chil- 

 dren, particularly the males. The flattening of the chest is most 



