THE PHASES OF LIFE. 855 



CHAPTER VI. 



THE PHASES OF LIFE. 



800. The child has at birth, on an average, rather less than one-third 

 the maximum length, and about one-twentieth the maximum weight, to 

 which in future years it will attain. 



The composition of the body of the newborn babe, as compared with that 

 of the adult, will be seen from the following table, in which the details are 

 more full than those given on p. 482. 



/ 



Weight of organ in percentage Weight of organ in 



of body-weight. adult, as compared 



, with that of newborn 



Newborn babe. Adult. babe taken as 1. 



Eye 0.28 0.028 1.7 



Brain 14.34 2.37 3.7 



Kidneys 0.88 0.48 12 



Skin 11.3 6.3 12 



Liver 4.39 2.77 13.6 



Heart 0.89 0.52 15 



Stomach and intestine 2.53 2.34 20 



Lungs 2.16 2.01 20 



Skeleton 16.7 15.35 26 



Muscles, etc 23.4 43.1 28 



Testicle 0.037 0.8 60 



It will be observed that the brain and eyes are, relatively to the whole 

 body-weight, very much larger in the babe than in the adult, as is also, 

 though to a less extent, the liver. This disproportion is a very marked em- 

 bryonic feature, and, as far as the brain and eye are concerned at least, has 

 a morphological or phylogenic, as well as a physiological or teleological, sig- 

 nificance. Inasmuch as the smaller body has relatively the larger surface, 

 the skin is naturally proportionately greater in the babe. It is chiefly by 

 the accumulation of muscle or flesh, properly so called, that the child ac- 

 quires the bulk and weight of man, the skeletal framework, in spite of its 

 being specifically lighter in its earlier cartilaginous condition, maintaining 

 throughout life about the same relative weight. 



801. The increase in stature is very rapid in early infancy, proceed- 

 ing, however, by decreasing increments. During or shortly before puberty, 

 there is again a somewhat sudden rise, with a subsequent more steady but 

 diminishing increase up to about the twenty-fifth year. From thence to 

 about fifty years of age the height remains stationary, after which there may 

 be a decrease, especially in extreme old age. 



802. The increase in weight is also very rapid at first, and proceeding, 

 like the height, with diminishing increments, may continue till about the 

 fortieth year. After the sixtieth year a decline of variable extent is gen- 

 erally witnessed. It is a remarkable fact, however, that in the first few days 

 of life, so far from there being an increase, there is an actual decrease of 

 weight, so that, even on the seventh day the weight still continues to be less 

 than at birth. 



803. The saliva of the babe is active on starch, and its gastric juice, 

 unlike that of many newborn animals, has good peptic powers, from which 

 we may infer that its digestive processes in general are identical with those 

 of the adult ; but the feces of the infant contain, besides considerable quan- 



