196 THEORY AND PRACTICE 



times seen as a symptom of some other disease, for instance 

 anaemia. Hard work often brings it on, especially on a hot day. 

 It occurs through a disturbance of the equilibrium of the nervous 

 system (sympathetic). When the condition comes through exer- 

 tion, the animal is exhausted and the heart is over-taxed. The 

 action of the nerves may be direct or reflex. Acute indigestion 

 may cause thumps. This form of the disease may come on 

 while the animal is standing quietly in the stable. 



Singultus or spasm of the diaphragm (hiccough) is caused 

 by excitation of the phrenic nerve center and it is thought that 

 this excitement is due to some form of indigestion. Too hard or 

 too fast work after a full meal is apt to cause hiccough and it may 

 be mistaken for palpitation. It may sometimes develop without 

 any apparent cause. The condition is seen most frequently in 

 fast horses. If a horse comes in from a run with hiccough and 

 in great distress, he may recover in twenty minutes, but if it 

 is thumps he may be laid up for several days. 



Semeiology. — There is increased effort with decreased power 

 of the heart. The pulse is irregular in every way. It is gen- 

 erally very rapid, say at seventy-five, but it is up and down and 

 the force of the beat is irregular. The result is passive conges- 

 tion of the lungs and there is rapid breathing with considerable 

 dyspnoea in a bad case. No signs of pain especially, but the 

 distress of the animal is great. There is a jugular pulse, disten- 

 sion of the veins of the head and neck and the palpitation of the 

 organ itself is sometimes so great as to shake the whole body. 

 In hiccough there is sudden contraction of the diaphragm, in 

 spasms, which also gives an impulse to the body, but you cannot 

 see the pounding of the heart on the ribs. Hiccough is not as fre- 

 quent as palpitation. You may get several hiccoughs in a minute 

 and on the other hand only one in the course of three minutes. In 

 palpitation there is apt to be two or three a second. Hiccough 

 may stop any time, while in palpitation the thumps keeps up for 

 one to two hours to a day or two. In palpitation the blood ves- 

 sels will be greatly dilated, while in hiccough they will not. 



Treatment. — In all cases there should be perfect quiet. If 

 the palpitation is due to organic disturbance of the heart's action 



