DISEASES OF HORSES 385 



may be poulticed above the fetlocks with mustard. Warm blanket- 

 ing, to promote perspiration, is to be observed in all cases in which 

 there is no excessive perspiration. 



If the disease becomes chronic we must place our reliance upon 

 alteratives and tonics, with such incidental treatment as special 

 symptoms may demand. Iodide of potassium 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 iodide 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 dis- 

 appearance of the acute symptoms, blisters 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 com- 

 bination 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 predisposed to subsequent at- 

 tacks. A long period of 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 uremic 

 poisoning, influenza, rheumatism, toxic agents, etc., they should re- 

 ceive prompt attention for their removal. Cerebral softening, ab- 

 scess, and sclerosis are practically inaccessible to treatment, other- 

 wise 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 determination of 

 blood or diminished arterial resistance, and passive when it accumu- 

 lates in the vessels of the brain, owing to some obstacle to its return 

 by the veins. 



Causes. Active cerebral congestion may be due to hypertrophy 

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

 of extreme heat, sudden -and great excitement, artificial stimulants, 

 etc. Passive congestion may be produced by any mechanical ob- 

 struction which prevents the proper return of blood through the 

 veins to the heart, such as a small or ill-fitting collar, which often 

 impedes the blood current, tumors or abscesses pressing on the vein 

 in its course, and organic lesions of the heart with regurgitation. 



Extremely fat animals with short thick necks are peculiarly 

 subject to attacks of cerebral congestion. Simple congestion, how- 

 ever is merely a functional affection, and in a slight or moderate 

 degree involves no immediate danger. Extreme engorgement, on 

 the contrary, may be followed by rupture of previously weakened 



