112 CHAPTER 11. 



force in the heart's action to propel forward distinctly a wave of blood, 

 or when the wave of blood which is propelled fonvard, is too small in 

 quantity to make its passage felt in the artery, we may often gain much 

 information by listening to the beats of the heart. 



Auscultation may also enable us to detect either structural or func- 

 tional disease of the heart. The heart, however, in the horse is but 

 seldom diseased primarily ; though it often becomes so, as a sequel of 

 pleurisj^ or rheumatic affections. 



217. Action of the Heart. 



When the heart is healthy its rhythms are firm and strong, and its 

 beats are as regular as the ticks of a clock, and the pulse is also firm and 

 regular. 



In disease the action of the heart may be feeble and even half para- 

 lysed, or it may be violent and over-excited. It is not our intention here 

 to enter into any consideration of the diseases or causes of the diseases 

 and affections of the heart. We shall only note its action as regards the 

 indications of the pulse. 



If the action of the heart is feeble, the pulse will in consequence be 

 feeble in tone, quick, fluttering, and often intermittent, and the impulse 

 given to the wave of blood in the arteries may be so feeble that the pulse 

 may be extinguished by the slightest pressure of the finger. 



The difference between the action of the heart in hea,lth and in some 

 debilitating diseases may in many respects be compared with the exer- 

 tions of a man in swimming. Whilst the man is strong and vigorous 

 his strokes are regular and trrae ; but should he become exhausted and be 

 in danger of being drowned, they become quick, irregular, and feeble. 



This comparison may perhaps afford some clue to the treatment re- 

 quired when the pulse is quick, in'egular, or feeble. It would be absurd 

 in the case of the drowning man to do anything which might still further 

 paralyse his already flagging muscular energy. It is equally absurd to 

 bleed or lower the horse in a case such as above described. 



If we are desirous of rendering assistance, we should not give depress- 

 ants iinder such circumstances to either the man or the horse, but rather 

 difi'usible stimulants with a view of rousing as far as possible the nervous 

 force, and thereby increasing the muscular energy ; until in the one case 

 the man has reached the shore, and in the other case the heart has kept 

 the horse's blood in circulation, so that it may be revivified and purified 

 by the action of the air in the limgs. 



On the other hand, in the earlier stages of inflammatory attacks, espe- 

 cially in those of a sthenic type, or when fever is present, it often happens 

 that the action of the heart is over-excited, and the pulse in consequence 

 is unduly full and strong. 



To the inexperienced bleeding and other depletives naturally suggest 

 themselves as the appropriate remedies. Collapse of the power of the 

 nervous system, however, sooner or later always follows excitement. Now 

 if during the period of excitement extreme measures of depletion are re- 



