VERTIGO— MEGRIMS. 31 



when any of the arterial trunks of the body are interrupted l)y liga- 

 ture : what is called anastomosis, or inosculation, takes place be- 

 tween the branches of the trunk proceeding from either side of the 

 ligature, by which inter-union, in the course of some months, the 

 circulation of the blood becomes perfectly re-established. When 

 the carotid artery was tied, it appeared to require twelve months 

 before the blood found courses to run to the brain with its wonted 

 freedom ; as soon as it had, the malady returned : so that, in fact, 

 all that was gained from the operation was a year's remission of 

 the disorder ; and this is all, I am afraid, we are likely to derive 

 by it. I have myself tied the posterior aorta in the dog success- 

 fully. For many months afterwards the animal followed me 

 about as usual ; and when I had him destroyed for the purpose 

 of preparation, I found ample circuitous vessels had been formed 

 to carry on the circulation with the same facility and freedom as 

 before the operation. 



PARALYSIS— PALSY. 



Definition. — A loss or diminution of the sensibility or mo- 

 bility of some part of the body ; commonly of both faculties. 



Kinds. — Dr. Cullen described four : — 1. Paralysis partialis , 

 palsy of some particular part or single muscle ; 2. Paralysis 

 hemiplegica, palsy of one side of the body, longitudinally ; 3. Para- 

 lysis paraplegica, ^^dX^y of one- half of the body or thereabouts, 

 transversely, as of the hind quarters; 4. Paralysis venenata, 

 palsy from the effects of poison. To these some veterinarians 

 have added a fifth kind, one they have denominated general 

 palsy ; but their cases in illustration have not borne them out in 

 this addendum : in fact, a general palsy, properly speaking, 

 amounts to an apoplexy. D'Arboval describes palsy as ambu- 

 latory, affecting first the posterior extremities, afterwards the 

 anterior, and finally returning to its original seat. There may 

 occur such cases : I never saw any. 



The Kind to which the Horse is most disposed is para- 

 lysis paraplegica. Hemiplegia but rarely occurs. 



The Symptoms of Paraplegia are very characteristic of 

 what ails the animal. The horse is down — unable to stand; nor 



