MEDICINAL USES 683 



tained experimentally by stimulation of sympathetic nerves, 

 and it is by such a stimulation that the action of adrenalin 

 can be best explained. Even its action on the heart is 

 in line with this theory, for although it slows the heart 

 when given intravenously, this is due to the rapid rise of 

 blood-pressure. In an isolated heart, or with divided vagi, 

 the first effect of adrenalin is to quicken the heart by 

 sympathetic stimulation. 



TOXIC EFFECTS. Excessive doses cause vomiting in dogs, 

 muscular tremors, rapid breathing, paralysis of hind ex- 

 tremities, dyspnoea, with failing respiration, congestion, 

 with visceral oedema and haemorrhage, and serous effusion. 



MEDICINAL USES. In veterinary practice adrenalin, 

 though sometimes administered in systemic disease, is 

 mainly employed as a local haemostatic in minor opera- 

 tions. Injected hypodermically, it renders the part ischaemic 

 and the operation comparatively bloodless. It must be 

 remembered, however, that it will not constrict the larger 

 vessels, but, by the absence of blood, these are more easily 

 detected and ligatured, before being severed. For surgical 

 purposes adrenalin is usually combined with a local anaes- 

 thetic such as cocaine, eucaine, or stovaine. Adrenalin 

 intensifies the action of the anaesthetic and limits its toxic 

 effects, for by constricting the arterioles of the part, the 

 entrance of the anaesthetic into the general circulation is 

 retarded or prevented, and its physiological action localised 

 and concentrated. 



In red- water in cattle and haemoglobinuria in horses, Zehl 

 has obtained successful results from the use of a 1 : 10,000 

 solution, in doses of five to eight fluid drachms injected 

 hypodermically. He has also found this solution beneficial 

 in laminitis, in which he injected 80 minims inside and out- 

 side each fore fetlock. In haemoglobinuria, Budd gave one 

 drachm of adrenalin chloride solution (1:1000) in three ounces 

 of water, and repeated this dose every three hours ; recovery 

 followed. Its use has been suggested in purpura haemor- 

 rhagica to diminish extravasation. Adrenalin is of un- 

 doubted value as a haemostatic in haemorrhage, but it must 

 be brought in contact with the bleeding part. It is indicated 

 in bleeding from the nose, stomach, bowels, uterus, vagina, 



