DISEASES OF HORSES 397 



produce suspension of the conducting motive power to the muscular 

 structures. Pressure upon, or the severing of, a nerve causes a 

 paralysis of the parts to which such a nerve is distributed. Apo- 

 plexy may be termed a general paralysis, and in nonfatal attacks is 

 a frequent cause of the various forms of palsy. 



General Paralysis. This can not take place without producing 

 immediate death. The term is, however, usually applied to paraly- 

 sis of the four extremities, whether any other portions of the body 

 are involved or not. This form of palsy is due to compression of 

 the brain by congestion of its vessels, large clot formation in apo- 

 plexy, concussion, or shock, or any disease in which the whole brain 

 structure is involved in functional disturbance. 



Hemiplegia, or Paralysis of One Side, or Half, of the Body. 

 Hemiplegia is frequently the result of a tumor in the lateral ven- 

 tricles of the brain, softening of one hemisphere of the cerebrum, 

 pressure from extravasated blood, fracture of the cranium, or it may 

 be due to poisons in the blood or to reflex origin. When hemiplegia 

 is due to or the result of a prior disease of the brain, especially of an 

 inflammatory character, it is seldom complete; it may affect only 

 one limb and one side of the head, neck, or muscles along the back, 

 and may pass off in a few days. 



Symptoms. In hemiplegia the attack may be very sudden and 

 the animal fall down powerless to move one side of the body; one 

 side of the lips, will be relaxed; the tongue may hang out on one side 

 of the mouth; the tail curved around sideways. An inability to 

 swallow food and water may be present and often the urine dribbles 

 away as fast as it collects in the bladder. Sensibility of the affected 

 side may be entirely lost, or only partial ; the limbs may be cold and 

 sometimes unnaturally warm. In cases where the attack is not so 

 severe the animal may be able to maintain the standing position, 

 but will have great difficulty in moving the affected side. In such 

 cases the animal may recover from the disability. In more severe 

 cases, where there is complete loss of movement, recoveries are rare. 



Laryngismus Paralyticus, or Roaring. This condition is char- 

 acterized by roaring, and is usually caused by an inflamed or hyper- 

 trophied bronchial gland pressing against the left recurrent laryn- 

 geal nerve, which interferes with its conducting power. A similar 

 condition LS occasionally induced in acute pleurisy, where the recur- 

 rent nerve becomes involved in the diseased process or compressed by 

 plastic exudation. 



Paralysis of the Rectum and Tail. This is generally the re- 

 sult of a blow or fall on the rump, which causes a fracture of the 

 sacrum bone and injury to the nerves supplying the tail and part of 

 the rectum and muscles belonging thereto. This fracture would 

 not be suspected were it not for the loss of motion of the tail. 



Symptoms. When due to mechanical injury of the spinal 

 cord, from a broken back or spinal hemorrhage, it is generally pro- 

 gressive in its character, although it may be sudden. When it is 

 caused by agents in the blood, it may be intermittent or recurrent. 

 Paraplegia is not difficult to recognize, for it is characterized by a 



