Chronic Hydrocephalus. Dropsy of the Ventricles. 113 



One of the most striking features of the disorder is the difficulty 

 of backing. In some cases he will back a few steps and then prove 

 unable to back farther ; in others he will show it best when heat- 

 ed with a journey ; in other cases still he will back well enough 

 under his own weight, but prove utterly unequal to the act if a 

 heavy man is placed on his back, or if hitched to a loaded wagon. 

 In backing with or without a rider the horse, pulled back by the 

 reins, inclines backward with his hind limbs extended forward 

 beneath the abdomen, his forefeet extended in front, and his back 

 arched ; he extends his head or turns it to one side, and when the 

 change in the centre of gravity endangers his equilibrium, he 

 draws back his forefeet without lifting them, each making a 

 groove in the ground, and at the same time he makes a disorderl)- 

 motion of the hind limbs to one side to restore the balance. In 

 default of this he may drop his quarter on the ground and perform 

 a back somer.sault on his rider. Even when he succeeds in bal- 

 ancing himself after dragging the forefeet back, the difficulty of 

 further backing is rather increased, as the nervous irritability is 

 enhanced by a continuance of the excitement. 



When hitched in a carriage the phenomena are virtually the 

 same ; when backed he extends or flexes the head, inclines the 

 body backward, and after a time loses his equilibrium, sometimes 

 executes a few disorderly steps backward, or throws himself vio- 

 lently to one side, or turns over backward in the shafts. 



The symptoms are always wor.se during hot, damp weather, and 

 when the animals are exposed to the full glare of the sun. The 

 milder cases can be worked without great inconvenience in winter, 

 while they become utterly useless in svmimer. 



Active exertion and increased rapidity of the circulation has a 

 similarly injurious effect. After a period of rest nothing amiss 

 may be noticed, while after a period of work in the sunshine the 

 symptoms become well marked and the difficulty of backing pro- 

 nounced. Plethora or full feeding aggravates, while spare, laxa- 

 tive diet, laxatives, rest or bleeding relieves. 



The affection may become complicated by more active inflam- 

 matory action leading to paroxysms resembling tho.se of meningo- 

 encephalitis ; — pushing against the wall, rearing up with the fore 

 feet in the manger, acting as if walking or trotting, etc. In 

 other cases the paroxysms resemble those of vertigo ; the animal 



