THE VITAL PRINCIPLE — THE BLOOD. 29 



of the mucous membranes. True chyle cannot 

 be formed without its agency ; its constituents 

 for the most part contain a large portion of 

 carbon and hydrogen, which are obtained from 

 the blood. Hence, while the bile is essential 

 to the process of digestion, its elimination is 

 one of the means for maintaining the purity of 

 the blood. It is from venous blood, in minute 

 vessels, termed venous capillary vessels, that 

 bile is secreted, and it is the only known true 

 secretion which is derived from this source, at 

 least as far as the higher animals are con- 

 cerned. 



Such, then, are some of the discoveries rela- 

 tive to life and its processes which science has 

 effected. Very limited, however, at the best, 

 are the researches of human philosophy. 

 Thoughtless men have sometimes objected to 

 mysteries in the revealed word of God ; but how 

 much greater are those which exist in that 

 department of the natural world to which our 

 attention has just been directed ! In it mys- 

 teries meet us at every turn. The phenomena 

 of feeling, muscular motion, the antagonism 

 between living bodies and the ordinary laws of 

 chemistry, the conversion of food into blood, 

 and the never-ceasing round of change which 

 takes place in the body itself, are all so many 

 mysteries. In the sight of God, then, let us be 

 clothed with humility, and thankfully receive 

 that revelation of his will which he has given 

 us — a revelation in which he has made the way 

 of redemption so clear that " the wayfaring men, 



