52 The Management and Treatment of the Horse, 



completely useless ; these fits occasionally seizing them if 

 "backed " or their heads raised suddenly, when they stagger 

 and fall. No doubt this results from a thickening of the mem- 

 branes of the brain, causing an effusion into the ventricles. 

 The late Professor Dick, of Edinburgh, showed me a case 

 in which bleeding, laxatives, alteratives, vegetable and 

 mineral tonics had been tried in vaio,but the employment 

 of setons over the front of the head and behind the poll 

 for three weeks completely restored it. The organ which 

 suffers chiefly is the heart. But it is the result of a state 

 of things the very opposite oi congestion or inflammation ; 

 it is affected mechanically, not from diseased actions. It is 

 deprived of its wonted vigour ; it is unable to empty itself in 

 its systolic and disastolic action. A portion of the blood 

 remains in the ventricles, the heart is feebly but irritably 

 labouring, agitating, and beating upon the same charge of 

 blood over and over again. The fibrine of the blood 

 attaches itself to the tricuspid and bicuspid valves and 

 their cords, as well as the corded tendinea and cortina 

 tendinea, by which (the passages being to a certain extent 

 choked at every involuntary contraction of the ventricles) 

 an escape of blood back into the ventricles takes place. 

 This state of the central pump will account for the 

 diminished if not suspended force from behind, and 

 hence the small, feeble, and almost bloodless pulse. 

 This was pointed out to me by the great friend of my 

 boyhood, the late Professor Dick, of Edinburgh, upwards of 

 twenty years ago. There is another symptom, which 

 in some cases occurs in * a most remarkable degree ; 1 

 allude to the great irregularity or inter mitt ency of the 

 pulse. Mr Haycock says, "I have observed it in some 



