128 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



spinal marrow, lodged within the spinal canal, or hollow of the back- 

 bone, is continuous with the brain anteriorly, and terminates in a 

 point in the sacrum (that part of the spinal column which imme- 

 diately precedes the tail) . The spinal cord gives off branches at each 

 of the spaces between the segments of the backbone. These branches 

 form nerve trunks which carry both sensory and motor impressions 

 and impulses. The spinal cord is a grand nerve trunk to carry mes- 

 sages to or from the brain and to and from the reflex centers con- 

 tained within itself. 



The brain is contained within the cavity of the skull and is con- 

 tinuous with the spinal cord; there is nothing to mark the place 

 where one leaves off and the other begins. The brain is the seat of 

 reason and intelligence. Voluntary effort originates from the brain. 

 Co-ordination, or harmony of movement, is controlled by the rear 

 portion of the brain, known as the cerebellum. 



The meninges are the membranes, three in number, which en- 

 velop the brain and spinal cord, and separate them from the bones 

 which form the walls of the cranial cavity and spinal canal. 



The sympathetic, also called the ganglionic, division of the ner- 

 vous system consists of two chains of ganglia, reaching from the head 

 to the tail, situated beneath the spinal column, one on either side. 

 The presence of the ganglia or enlargements on the cords give them 

 their chain-like appearance. 



The sympathetic nerves are closely connected with the cerebro- 

 spinal nerves, but are not under the control of the will. 



INFLAMMATION OF THE BRAIN AND ITS MEMBRANES ( STAGGERS ). 



Inflammation of the brain is technically termed encephalitis 

 and of its membranes cerebral-meningitis, but as both conditions 

 usually occur together, and since it is practically impossible to distin- 

 guish one from the other by the symptoms shown by the diseased 

 animal, they may as well be considered together here as varieties of 

 the same disease. Staggers, coma, frenzy, etc., are terms that are 

 sometimes applied to this disease in its different forms or stages. 



Causes. Severe blows on the head with a hard object, or the 

 head coming violently in contact with the ground or other hard sub- 

 stance in a fall, may be followed by encephalitis. Irritation caused 

 by tumors in the brain may produce inflammation. Food containing 

 deleterious matters for example, ergot and other fungi which con- 

 tain a narcotic principle is the most frequent cause of this affection, 

 and hence it is often called grass staggers and stomach staggers. 

 Highly nitrogenous foods are blamed for causing this disease. Para- 

 sites, mineral and narcotic poisons, hot weather, and severe exertion 

 or excessive excitement may cause this condition. Inflammation of 

 the brain may occur as a complication of some infectious disease or 

 may follow some forms of indigastion. In many localities certain 

 plants have the reputation of causing staggers. 



Symptoms. The symptoms vary much, but a careful observer 

 will detect a trouble connected with the nervous system without much 

 uncertainty. The first signs may be those of frenzy, but generally 

 at the start the animal is dull and sleepy, -with little or no inclina- 



