8 June, 1908.] Diseases of the Skin. 339 



prussic acid lotion is most efficacious — two drams of prussic acid to a quart 

 of water is sufficiently strong. It should be sopped on to the itchy part 

 two OT three times a day, and being a deadly poison care should be taken 

 mat it is not allowed within the reach of other animals or children. When 

 used for dogs it is necessary to muzzle the animal so that he may not lick 

 the part otherwise fatal poisoning will result. 



Nettle-rash or Urticaria. 



This acute affection of the skin is manifested in the horse, dog and 

 pig. In the latter animal it has been mistaken for swine fever on account 

 of the skin lesions, but on observation for a dav or two such a mistake is 

 inexcusable. 



/. 



THE BLEBS OF NETTLE-RASH. 



Symptoms. — The characteristic symptoms are manifested very sud- 

 denly. I'here may or may not be a preceding itchiness. The skin becomes 

 covered wath elevated " blebs'"' (vesicles) or boils exactly resembling those 

 produced by a nettle-sting {urtica=-di nettle). The skin of the neck and 

 shoulders is usually first affected, then that of the back and buttocks. 

 The boils vary in size and may coalesce forming blotches or raised 

 patches the size of a man's hand containing a watery or serous fluid. The 

 hair on the elevated parts is raised and when the hand is passed over the 

 surface of the skin a " hobnailed " impression is felt. As a rule the 

 symptoms subside as rapidly as thev appear and in the course of a day 

 all is well again. 



Causes. — Nettlerash frequently occurs on abrupt change of diet 

 especially in gross or full-feeding animals ; indigestible or unusual food 

 is a common cause. In man the eating of fish sometimes precipitates an 

 attack. me disease also occurs along with catarrh, jaundice or other 

 derangement of the digestive tract. In all these cases it is probable that 

 the condition arises from irritation- of the skin from abnormal sub- 

 stances circulating in the blood which have been absorbed from the 

 alimentary canal. A sudden chilling of the skin when the bodv is over- 

 heated often results in the development of the disease. In this case it 



