1 1 4 ELEMENTS OF PH YSIOL OGY 



200. But Alcohol affects the Heart itself. " The valves, 

 which consist of folds of membrane, lose their suppleness 

 and become diseased and weakened. The muscular fiber 

 of the heart is replaced by fatty cells, so that the power of 

 contraction is greatly reduced. These derangements are 

 likely to cause death from sudden failure of the heart itself, 

 or from rupture of the weakened blood vessels, and oozing 

 of the blood in the brain, producing apoplexy " (G. H. 

 McMichael, M.D.). The condition of the heart mentioned 

 above is called fatty degeneration of the heart. 



201. Hemorrhage is a flow of blood from an injured 

 blood vessel. When the wound is slight, the clotting of the 

 blood stops the flow. Clotting is rapid in the blood of 

 healthy persons and slow in the blood of poorly nour- 

 ished persons. Blood does not spurt from a cut vein but 

 flows in a slow stream. When an artery is cut, the blood 

 comes forth in a jet, with stronger spurts at each throb of 

 the heart. In a large artery the pressure is so strong that 

 it forces away the clot as fast as it is formed, so that death 

 may result from loss of blood. 



202. Tobacco Heart, or Trotting Heart. Tobacco, unlike 

 alcohol, does not dilate the blood vessels of the skin ; to- 

 bacco users are often pale from want of blood in the skin. 

 We thus see why tobacco users develop a stronger craving 

 for drink than non-users, because the alcohol has, in some 

 respects, an effect opposite to that of tobacco. However, 

 heart action is temporarily increased when tobacco is used. 

 In the present chapter you learned that the sympathetic 

 nerves increase the heart action and the vagus nerves hold 

 ft in check. The vagus is partially paralyzed by to- 

 bacco, and the heart beats with more force, thus ex- 

 hausting itself. The pulse of the habitual user shows 

 unmistakably the injury done to the heart. It loses the 

 firm steady beat of health and becomes irregular. Most 

 of the time its beat is feeble, but for a short period its 



