1. The value of aureomycin in the treatment of heartwater has been
established. It is considerably more effective than the sulphonamides.
2. The minimal therapeutic dose for sheep appears to be 2•5 mg. per lb.
administered intravenously either as a single dose or in divided doses at intervals
of 24 hours.
3. Doses smaller than the curative dose have a marked effect upon the
course of the disease.
4. In cattle even advanced cases have responded promptly to administration
of 2 to 2•5 mg. per lb. It was possible that doses as small as 1 mg. per lb. were
5. Administered in the incubation stage of the disease in amounts approximately
double the curative dose it had a marked effect upon the subsequent course
of the disease.
6. Prophylactic or curative administration in doses up to 20 mg. per lb. did
not interfere with immunity production.
7. Aureomycin alone or in combination with a sulphonamide is suggested
at present as the drug of choice for treatment, or together with live virus for
This work was facilitated by the supply in very generous quantities of aureomycin
hydrochloride with sodium glycinate by the Director, Lederle Laboratories,
Pearl River, N.Y., U.S.A., to whom we wish to take this opportunity of expressing