SUNSTEOKE. 571 



and to " cool " the animal down with laxative food, and a mild 

 dose of physic, if necessary. The case hardly admits of treatment, 

 if the complaint be due to nervous disease ; for, in the horse, we 

 require at least, " practical somidness," and not mere prolong- 

 ation of life, as might be sufficient in hmnan practice. Even for 

 stud purposes, an animal afflicted with brain disease, would scarcely 

 be worth keeping ; considering the marked influence of heredity in 

 this complaint. 



Sunstroke. 



DEFINITION. — A state of sudden unconsciousness and paralysis 

 brought on by exposure to great atmospheric heat, generally in- 

 tensified by muscular exertion. 



NATURE OF THE DISEASE.— In human medicine, there axe three forms 

 of sunstroke recognised : (1) Heat exhaustion, causing failure of the action of 

 the heart. (2) Heat shock, coup de soleil, or sunstroke proper, in which, 

 exposure to great heat, often aided by intense glare, appears to paralyse the 

 nerve centres of breathing and of blood circulation by sudden shock, so that 

 the lungs and heart are unable to perform their functions. (3) Heat fever or 

 heat apoplexy, in which the nerve centres become exhausted from over- 

 stimulation due to prolonged exposure to heat. We have good reason to 

 believe that the temperature of the body is regulated by a heat centre in the 

 nervous system. As nerves become insensible to a stimulus by which they 

 have been highly excited for a long period ; we may account for the sudden 

 rise in temperature and consequent climax in cases of heat apoplexy, by 

 supposing that great and continued heat had so over-stimulated the heat 

 centre, that it had at last lost its power of control, with the result that the 

 tempera.tm'e rises to such an extent as to arrest the action of the lungs and 

 heart, to a greater or less extent. I believe every one of the scores of cases of 

 sunstroke which I have seen among horses in hot climates, came under the 

 heading of heat apoplexy. 



SYMPTOMS. — The history is, generally, somewhat as follows : 

 The horse, who, in many cases, had been previously dull and 

 breathing quickly (with, of course, distended nostrils), is taken 

 out to work, which he does fairly well (although an experienced 

 person would observe that he was much more distressed than he 

 ought to have been), until, more or less suddenly, he totters; 

 his legs give way under him ; and he falls down in an in- 

 sensible condition. He may then struggle convulsively, get up 

 and throw himself down in a most dangerous manner ; or, 

 while lying on the ground, he may make frantic efforts to 

 get up, which he is unable to do owing to his being paralysed 

 behind, and will madly dash his head on the ground. In 

 these convulsive efforts, he often inflicts terrible injuries on him- 

 self. Paralysis of the hind quarters is a well marked symptom 

 of sunstoke in the horse. Others will remain lying down, as 

 if dead : these are the hopeful cases. In all such instances. 



