ON THE FUNCTIONS OF LIFE. 953 



That the forces of life are greatly modified by 

 conditions of the brain and nervous system, is 

 evident from the fact, that respiration, on which 

 they all depend, is a voluntary process. Under 

 the influence of hope, love, joy, confidence, and 

 whatever tends to excite pleasurable emotions, 

 the lungs expand with freedom, by which the 

 blood is abundantly supplied with caloric, con- 

 verted into a bright scarlet fluid, the force of its 

 circulation augmented, digestion, sanguification, 

 nutrition, and all the other functions of life, per- 

 formed with alacrity. But when the brain is 

 paralyzed by grief, fear, despair, or by the re- 

 peated shocks of adverse fortune, the individual 

 almost forgets to breathe, until a feeling of op- 

 pression warn|^him to take a deep inspiration, 

 which is only another name for the boding sigh. 



The supply of animal heat by respiration is 

 diminished, the action of the heart enfeebled, the 

 circulation through the lungs and general system 

 is languid, the extremities are cold, perspiration 

 is checked, the surface is pale or sallow, and the 



of ill health, and a long train of moral evils, that nearly all the 

 causes of nervous maladies may be traced to anxiety of mind, in- 

 tensity of thought, sedentary avocations, andplenary indulgence, 

 that the besetting sin of the present age, is not so much that 

 of intemperance in eating and drinking, as reading and thinking, 

 the penalty of which, alas, falls far more frequently on those 

 who labour for the good of society, than on those who live in 

 luxury and idleness. But he adds, of the mode in which the 

 mind operates on the body, we know as little as we do, in regard 

 to the modus operandi of gravity and magnetism, (pp. 134 146 

 -150.) 



