38 



MOBILITY OF CHEST. 



It will be seen, in each of the above nativities, that the dark-complexioned men 

 surpass the blonde portion as to girth of chest, although the latter average more than 

 double the number of the former. In the case of the natives of the United States, a 

 Hke comparison of complexion with stature developed a precisely similar result, namely, 

 that the dark men surpassed the light in height. This might at first seem in itself suffi- 

 ciently explanatory, as increase of girth of chest is, to a certain extent, proportioned to 

 increased height in the same race; but, if the comparison be carried further, it will be 

 found that this relation is not sustained. 



Table slwicing the relation of stature to girth of chest in five nativities, where each nativity has been 



classified according to complexion. 



' The mean stature of Irishmen i>roved to he identical for dark and light complexions. 



From the foregoing tables it does not appear that any recognizable relation exists 

 between circumference of chest and stature when complexion is made the basis of classi- 

 fication of the subjects of the inquiry. Ireland, for example, which ranks nearly first 

 in the scale in excess of girtli of chest of its dark men, exhibits no difference whatever 

 in mean stnture as dependent upon complexion. 



Mobility of the chest. — The mobility of the chest is so intimately connected 

 with the vital capacity that it is a matter of regret that the spirometer could not be made 

 use of during the draft. In default of this, however, it will be observed that the 

 records of the expansibility of the chest are extremely copious. Hutchinson was very 

 positive in his opinion that, although the vital capacity increased in very regular rela- 

 tion to the stature — not the length of the body, but the entire height — yet that it was 

 •principally governed by the mohUlty of the chest. In the treatise already referred to, he 

 states that vital capacity has no relation, either to the depth or the circumference of the 

 chest; and further experiments seem to ha,ve strengthened these views, for in a later 

 work they are re-asserted in the following words : 



"Although the vital capacity increases with the stature, yet the absolute admeas- 

 urement of the chest does not augment in any of its dimensions with the general 

 lieight; because the volume of breath is relative to the mobility of the thoracic bound- 

 aries, just as the volume of blast from the common domestic bellows is chiefly relative 

 to the movement of the walls of that machine, and not to its absolute size. For 

 instance, two bellows, of exactly the same dimensions, tlie one made of fine kid leather, 

 and the other of some thick hide, would displace dissimilar volumes of air, because 

 thcii- mubility would be dissimilar. For the same reason, a different mobility in two 



