108 THE HUMAN MOTOR 



tends to become curved in the opposite direction to the load, and 

 under a continuous pressure the column bends and appreciably 

 reduces its length. 



Natural aptitude for any trade or occupation is influenced by 

 the proportions of the limbs, long limbs having large but slow 

 movements ; short limbs denote speed. Thus the woodcutter, 

 the blacksmith, the sawyer, etc., can exeit the more force or effect 

 the longer the arm at the extremity oi which is the tool. The 

 shape of the body is often, on this account, a guide for the choice 

 of workmen suita'ble to this or that work ; but it is not an absolute 

 guide, because " adaptation " is an extremely important factor ; 

 thus a certain fencer excelled despite his small stature, which put 

 him at a disadvantage and exhausted his forces. As a rule, men 

 are organised and made to work in a certain way, because it is 

 thus that their work is most economical. With regard to age, it 

 is claimed that the strength of the human body is at its maxi- 

 mum between the ages oi 25 and 40. In fact, the skeleton does 

 not achieve its consolidation, its* ossification, and its welding 

 together until about its twentieth year ; 16 to 18 for the scapula, 

 which in developing presents large surfaces to the muscles for their 

 insertions ; 18 years for the humerus ; 20 to 25 for the ulna, ilium, 

 and femur ; 25 to 30 for the vertebral column. The bones of the 

 hand themselves do not complete their ossification until the age 

 of 12 to 13 years. Hence the importance ol not overstraining 

 the young, and not deforming organs, thereby condemning them 

 to develop abnormally. In fact, science should always protest 

 against the practice of making children work before their 15th 

 year, for this causes a misshapen, crippled and stunted humanity. 

 Where are the legislators who have sufficient courage to check 

 this social evil ? 



77. (ii) Stature. Stature is the vertical dimension of the 

 body, or the height when a man, standing, is measured by 

 means of an anthropometric measure (see Technics, 201). Often 

 the " height standing " is distinguished from " the height sitting," 

 in the latter case, the subject being seated so as to measure the 

 length of his bust only. 



The average height of an adult is 165 centimetres, varying 

 according to the race and the country, its lowest and highest 

 limits being 125 centimetres and 199 centimetres. In France 

 the average stature is 164'6 cms. ; (it was 1*9 cms. more in 

 1725, and was 166'5 cms. two centuries ago). ( x ) 



That of woman is 10 to 11 centimetres less than that of man, 

 but the difference was only from 5 to 7 centimetres at the 



(>) L'abb6 de Fontenu, Hist. Acad. Roy. Sc., 1725, p. 16. 



