AND ANIMAL LIFE. 71 



is secreted, or of the quantity which is already 

 poured out, it will not be difficult to arrive at 

 certain general laws which regulate the pheno- 

 mena. Every kind of exercise is a stimulus to 

 the blood ; it quickens its motion and improves 

 its properties, and these effects speedily excite 

 those parts of the system appropriated to secre- 

 tion. The abdominal viscera, without excep- 

 tion, receive the invigorating impulse, indicated 

 by the desire of food and the greater power of 

 assimilation ; the colour of the countenance and 

 the temperature of the body, and every natural 

 evacuation, is similarly benefited. But if the 

 body, instead of enjoying gentle exercise, be in- 

 active or subjected to constraint, the above 

 functions become irregular or imperfect ; or if 

 an individual be suffering from depressing pas- 

 sions of the mind, the appetite becomes almost 

 immediately fastidious or feeble ; and a variety 

 of other symptoms are present, which show that 

 the defect in the desire of food and the energy 

 of digestion is merely one of a series of conse- 

 quences flowing from the want of oxygenated 

 blood and a regular distribution of it. We have 

 no proof that the nerves in the kidneys secrete, 

 and we have as little evidence that the same 

 agents have that important office in the stomach ; 

 but if we suppose with WILSON PHILIP that 

 these act on the properties of the blood, evolv- 

 ing, in a manner unknown to us, the specific 



