'COMMON THINGS MAN. 



supplied. It may, however, be assumed that in extreme climates, 

 whether hot or cold, the body arrives at its full height sooner 



Fig 19. 



than in temperate climates ; in towns sooner than in the country, 

 and in plains sooner than in mountainous districts. 



49. The development of the body in bulk is slower than its 

 growth in height. A new-born infant has upon an average about 

 a twentieth of the weight which it will acquire upon attaining its 

 greatest development, which takes place in general for men at 40 

 and for women at 50. 



During the first year after birth, the increment of weight is 

 about 5^ of all that it will receive during its subsequent existence ; 

 and the increase of weight received from the 15th to the 20th year 

 is even greater than that which is acquired in the first five years. 



50. On arriving nearly at the limit of his stature, the male 

 passing from youth to manhood undergoes several organic changes. 

 His bones having acquired a larger proportion of the earthy con- 

 stituent, have increased strength, his muscles are more developed 

 and powerful. His voice losing the feminine pitch which charac- 

 terises boyhood, becomes almost suddenly much more grave, and 

 his beard is rapidly developed. 



The corresponding changes in the female organism are manifested 

 somewhat earlier, and show themselves by external forms familiar 

 to every eye. The chest becomes enlarged, the shoulders expanded, 

 and the pelvis acquires greater width, and the forms of womanhood 

 become conspicuously visible. In temperate climates these changes 

 are manifested at from 14 to 16 years of age. In warm climates 

 they take place at from 10 to 11, and in colder countries are post- 

 poned to 17 or 18. 

 78 



