224 Human Physiology. 



even among the more comfortable portion of the agricultural, 

 labourers, instances of great longevity are very common. With 

 a good stock of vitality, freedom from care, and tolerably 

 healthy habits and conditions, there need be no lack of cen- 

 tenarians. 



Length of life seems to be in some proportion to slowness of 

 development. Animals that come quickly to maturity are short 

 lived. The horse, which is old at thirty, is in full maturity at 

 four or five. Man, who lives from eighty to a hundred years, 

 matures at twenty or twenty-five. Physical precocity is often 

 a mark of shortness of life, as mental precocity is sometimes. 

 In the rare instances of puberty at seven, old age has come on 

 at thirty or forty. 



We know but little of the human soul, or how it lives in, and 

 acts upon and through the human body. We know little of 

 the human body, or even of the matter of which it is composed, 

 and the forces by which its functions are performed. What we 

 can see is, that an Infinite Wisdom and Power has ordered all 

 its parts, and that it is our duty to keep it, as far as in us lies, 

 in perfect health, vigour, and in the uses for which it was 

 designed by our Creator. 



