82 
Surra 
The arsenious acid was administered after feeding. 
The toxic dose is 2 to 3 grammes for ponies, and 4 to 5 grammes for 
horses. 
Arsenious acid administered in solution- (Loeffler and Ruehs) has a 
more toxic effect than when given in bolus. 
One gramme in solution is fatal for ponies weighing 250 lbs. 
This is shown in the following table : 
Pony 
no. 
Weight 
lbs. 
Dose of arsenious 
acid sol. c.c. 
Results 
1 
225 
600 
No symptoms. 
2 
215 
800 
Colic, off feed for 2 days. 
3 
350 
1000 
Colic, off feed for 3 days. 
4 
250 
1000 
Died in 24 hours. 
Arsenious acid injected subcutaneously. 
The subcutaneous method of administering arsenious acid is not a 
suitable one. Even when highly diluted (1 in 1000) the injected fluid 
does not readily become absorbed and causes a large oedematous swell¬ 
ing, accompanied with pain and inflammation which, in some cases, results 
in necrosis of the skin. 
• Pony no. 5. 250 lbs., was injected with 100 c.e. arsenious acid (1 in 1000). Swelling 
at seat of inoculation. Pony was off feed for three days. 
Mule no. 6. 427 lbs., was injected with 500 c.c. arsenious acid (1 in 1000); 250 c.c. 
was injected on either side. Large swellings at seat of inoculation resulted. The mule 
was off feed for two days. After several days the skin sloughed and the mule was 
destroyed. 
Mule no. 7. 630 lbs., was injected with 0-5 gm. arsenious acid dissolved in 20 c.c. 
glycerine. Large swelling at seat of inoculation, which persisted for several days. 
Sloughing of the skin followed. 
Pony no. 8. 220 lbs., received 0-75 gm. Arsenious acid dissolved in 50 c.c. of water 
containing 0'75 gm. sodium bicarbonate. Died in 16 hours. 
Arsenious oxide injected intravenously. 
Mule no. 9. 549 lbs., was injected with 100 c.c. of arsenious acid (1 in 1000). Showed 
no symptoms. 
Mule no. 10. 550 lbs., was injected with 500 c.c. arsenious acid (1 in 1000). Mule 
was off feed for two days. 
Horse no. 11. 900 lbs., was injected with 1 gm. arsenious acid dissolved in 250 c.e. of 
water containing 1 gm. of sodium bicarbonate. Symptoms of colic, followed after several 
days by paralysis of hind quarters. Destroyed. 
