208 BUKEAIJ OF ANIMAL INDUSTRY. 



of the blood vessels of the brain, etc., all have a tendency to 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. Apoplexy may be termed 

 a general parah'sis, and in nonfatal attacks is a frequent cause of the 

 various forms of palsy. 



General paralysis. — This can not take place without producing imme- 

 diate death. The term is, however, usually applied to paralysis of the 

 four extremities, whether any other portions of the bod}^ are involved 

 or not. This form of palsy is due to compression of the brain by con- 

 gestion of its vessels, large clot formation in apoplexy, concussion, or 

 shock, or any disease in which the whole brain structure is involved 

 in functional disturbance. 



Hemiplegia^ or jyaralysis of one side^ or lialf.^ of theTjody. — Hemi- 

 plegia is frequently the result of a tumor in the lateral ventricles of 

 the brain, softening of one hemisphere of the cerebrum, pressure from 

 extravasated blood, fracture of the cranium, or it may be due to pois- 

 ons 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 afl'ect only one limb and one 

 side of the head, neck, or muscles along the back, and ma}^ pass ofl; in 

 a few days after the disappearance of all the other evidences of the 

 primary aflfection. In the majority of cases, however, hemiplegia 

 arises from emboli obstructing one or more blood vessels of the brain, 

 or the rupture of some vessel the wall of which had become weakened 

 by degeneration and the extravasation of blood. Sensibility in most 

 cases is not impaired, but in some there is a loss of sensibility as well 

 as of motion. In some cases the bladder and rectum are involved in 

 the paralysis. 



Symptoms. — In hemiplegia the attack rpay be very sudden, and the 

 animal fall down powerless to move one side of the bod}", 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 

 or water may be present, and often the urine dribbles away as fast as 

 it collects in the bladder. Sensibility of the afl'ected side may be 

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

 unnaturally warm. In cases wherein the attack is not so severe the 

 animal maj' be able to maintain the standing position, but will have 

 great difiiculty in moving the aflfected side. In such cases the animal 

 may recover from the disability. In the more severe, where there is 

 complete loss of the power of movement, recoveries are rare. 



Paraplegia.^ or transverse paralysis of the hind extremities. — Paralysis 

 of the hind extremities is usually due to some injury or inflammation 

 affecting the spinal cord. (See "Spinal meningitis," p. 211, and 

 "Myelitis," p. 212.) It ma^' also be due to a reflex irritation from 



