PALPITATION. 551 



and somewhat varying as to their modes of operation, are in 

 the horse of more frequent occurrence than has hitherto been 

 recognised. They are in him intimately connected with hard 

 work, particularly work of a fast and exciting character, the 

 excitation and suddenness which attends its execution seeming 

 to have a direct influence upon all animals, although more 

 distinct and appreciable with some than others. 



In many of its forms nervous irritability or palpitation, 

 although very troublesome and somewhat inexplicable, often 

 seemingly connected with disturbance of the normal relations 

 which ought to subsist between the vagus nerve and the car- 

 diac ganglia, is yet more susceptible of management and suc- 

 cessful treatment than the cases dependent upon structural 

 disease of the heart or pericardium, where the opposition offered 

 to the flow of the blood is greater than the power at command 

 to drive it. 



Symptoms. — Palpitation is ordinarily accompanied with in- 

 creased frequency and apparent force of the heart's action. 

 The action may be regular, or the irregularity may partake of 

 alteration either in force, quickness, or frequency, often passing 

 into the more advanced condition of cardiac failure, inter- 

 mittency. The irregularity and intermittency may regularly 

 pass through a certain cycle in a given time, or the cardiac 

 action may seem completely confused. The palpitation may 

 be continuous, or occurring only at intervals, or in paroxysms, 

 depending upon the causes of its development, or upon 

 some very obvious immediately exciting influences. Although 

 actual pain is rarely a marked feature, there are usually observed 

 such general symptoms as anxiety, restlessness, and hurried 

 breathing ; while in paroxysmal seizures, dependent on nervous 

 irritability and disturbance, I have observed faintness and 

 actual syncope. 



In some the arterial pulse will indicate, by responsive throbs, 

 the heart's action ; in others the pulsatory wave is weak or 

 feeble, while the cardiac action is tumultuous, or regurgitative 

 action in the large veins of the neck may be the most distinc- 

 tive feature ; this latter feature is particularly the case when 

 the condition has been of some time standing, and the right 

 heart is structurally impaired. 



Treatment. — This disturbance of function and perversion of 



