66 Management and Treatme^it of the Horse. 



rendering tliem completely useless ; these fits 

 occasionally seizing them if *' backed" or their 

 heads raised suddenly, when they stagger and 

 fall. IN'o doubt this results from a thickening of 

 the membranes 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 vain, 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 

 of 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, agitat- 

 ing, 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 ac- 

 count 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 



