306 
Cure of Surra 
interval was extended to three and four days, relapses occurred. In 
the third system of treatment (arsenious acid solution, atoxyl and 
arsenious acid in bolus), the interval between the first, second, and 
third, series of doses should be four days, and eight days between the 
third and fourth series. 
(c) If the animal is in a very debilitated condition, it is advisable 
to clear the circulation of trypanosomes by one or more injections of 
atoxyl and feed carefully for several days before administering arsenic 
by mouth. 
( d ) Cases which relapse after treatment should be put on a second 
course with increased doses, either by the same or a different system 
of dosage. 
In cases of relapse, and also where treatment is not well tolerated, 
it is often advantageous to change the system of dosage. 
(e) Whenever possible, cases should be kept under observation 
for a period of two to three months after completion of treatment. 
Relapses generally occur within a period of six weeks. 
( f ) It is possible to cure Surra by a single dose of arsenic. This 
is not a practical method, as the amount of arsenic requisite produces 
severe symptoms of poisoning and a large percentage of cases ends 
fatally. 
Pony C 7 recovered after a single dose of 1 gm. arsenic in bolus. 
Mule C 44 recovered after a single dose of 3 gms. arsenic in bolus. 
Pony C 30 recovered after a single subcutaneous injection of 
200 c.c. of a 4°/ 0 solution of arsacetin. 
Pony C 31 recovered after a single subcutaneous injection of 
100 c.c. of a 10 °/ 0 solution of soamin. 
PLATES XXII TO XXVII. 
Photographs of the Transport Ponies which recovered after treatment for Surra. 
The first photographs were taken at the time of their arrival at the Laboratory. The 
second photographs were taken after the three months period of observation before the 
animals were returned to the Transport Corps. 
