DISEASES OF THE NERVOUS SYSTEM. 217 



If this treatment fails to give relief, the disease will pass into the 

 advanced stages, or, if the animal has been neglected in the early 

 stages, the treatment must be supplanted with the hypodermic injec- 

 tion of ergotin, in 5-grain doses, dissolved in 1 dram of water, every 

 six hours. The limbs may be poulticed above the fetlocks with mus- 

 tard. Warm blanketing, to promote perspiration, is to be observed 

 always when there is no excessive perspiration. 



If the disease becomes chronic (encephalitis or meningitis), we 

 must place our reliance upon alteratives and tonics, with such inci- 

 dental treatment as special symptoms may demand. lodid of potas- 

 sium in 2-dram doses should be given three times a day and 1 dram 

 of calomel once a day to induce absorption of effusions or thickened 

 membranes. Tonics, in the form of iodid of iron in 1-dram doses, to 

 which is added 2 drams of powdered hydrastis, may also be given 

 every six or eight hours, as soon as the active fever has abated. 

 After the disappearance of the acute symptoms, blisters (cantharides 

 ointment) may be applied behind the poll. When paralytic effects 

 remain after the disappearance of all other symptoms, sulphate of 

 strychnia in 2-grain doses, in combination with the other tonics, may 

 be given twice a day and be continued until it produces muscular 

 twitching. In some cases of paralysis, as of the lips or throat, benefit 

 may be derived from the moderate use of the electric battery. Many 

 of the recoveries will, however, under the most active and early 

 treatment, be but partial, and in all cases the animals become pre- 

 disposed to subsequent attacks. A long time should be allowed to 

 pass before the animal is exposed to severe work or great heat. 

 When the disease depends upon mechanical injuries, they have to be 

 treated and all causes of irritation to the brain removed. If it is 

 due to stable miasma, uremic poisoning, pyemia, influenza, rheuma- 

 tism, toxic agents, etc., they should receive prompt attention for their 

 removal or mitigation. 



Cerebral softening, abscess, and sclerosis are practically inacces- 

 sible to treatment, otherwise than such relief as may be afforded by 

 the administration of opiates and general tonics, and, in fact, the 

 diagnosis is largely presumptive. 



CONGESTION OF THE BRAIN, OR MEGRIMS. 



Congestion of the brain consists in an accumulation of blood in the 

 vessels, also called hyperemia, or engorgement. It may be active or 

 passive — active when there is an undue accumulation of blood or 

 diminished arterial resistance, and passive when it accumulates in 

 the vessels of the brain, owing to some obstacle to its return by the 

 veins. 



Causes. — ^Active cerebral congestion may be from hypertrophy of 

 the left ventricle of the heart, excessive exertion, the influence of 



