On the confusion of two different diseases under the name of rubella (rose-rash).

Dukes described a condition similar to that noted earlier by Filatov (No. 5503). Dukes called it the “fourth disease”, distinguishing it from scarlet fever, measles, and rubella on the ground that an attack of any of these diseases gives no immunity. The autonomy of this disease (“Filatov–Dukes disease”) is not universally accepted.