Symptoms. Diagnosis. Treatment. 621 



pressure and respiratory disturbance. If the loss of heat be 

 diminished owing to a high external temperature or close crowd- 

 ing of animals and the body heat be increased by muscular exer- 

 cise, the temperature of the animal body may be raised so high 

 (40'' to 45° C) that nerve paralysis may be produced without 

 the direct effect of the sun at all. It is quite easily understood 

 tliat a general rise of body temperature is scarcely ever absent 

 when an animal is exposed to the direct rays of tlie sun. A 

 sharp distinction between sunstroke and heatstroke is upon 

 these grounds both impracticable and unnecessary. 



Experimental evidence has recently been furnished by Marinesco that nervous 

 symptoms may be caused both by the direct rays of the sun, and also by an in- 

 crease in the boily temperature in animals kept in very hot but quite dark boxes. 



Christiani has demonstrated the diplococcus of sporadic meningitis in the 

 cerebrospinal fluid of horses that have died from heatstroke. But in these cases 

 there may have been primary meningitis owing to the unfavorable effect of the heat. 



Symptoms. In the earliest stages there is a rapidly pro- 

 gressive dullness and depression, the gait is uncertain and 

 stumbling, sweating is observed, and the expression of the face 

 is anxious. There is palpitation of the heart, the pulse is accel- 

 erated and weak, and respiration difficult. The mucous mem- 

 branes are in the early stages injected, but afterwards become 

 pale and even bluish. The temperature may be as high as 

 45° C or even higher. In rare cases, the animals show 

 symptoms of excitement which may amount to mania. 

 Towards the end, there is violent trembling, the animals 

 falling to the ground and dying in convulsions, if prompt assist- 

 ance is not forthcoming. In some cases death is sudden with- 

 out any remarkable disturbance of health having been observed, 

 in other cases animals die in from one to three days. 



In the soealled summer heaves ("Sommerdampfigkeit") Bon- 

 gartz observed sudden difficulty of respiration, causing heaving move- 

 ments of the entire body. "While going uphill or drawing a heavy load, 

 animals often fell, and sometimes dropped dead. If brought into warm 

 stables respiration remained difficult for some hours, and there was 

 marked dullness. During cooler or wet weather, there was a rapid im- 

 provement in their condition. In cases where the attacks occurred re- 

 peatedly, the animals became emaciated. 



Diagnosis. In making a diagnosis the following conditions 

 must be carefully excluded, acute infectious diseases, and es- 

 pecially septicemic conditions (anthrax, swine erysipelas) en- 

 cephalitis, relapses in cases of chronic hydrocephalus, epilepsy, 

 congestion or edema of the lungs. Special importance attaches 

 to the last two since they are likely to be set up by the same 

 external influences. 



Treatment. If possible animals should be placed in a 

 shady, cool spot or in water, and cold water should be poured 



