The Collaborative International Dictionary of English v.0.48:

Dropmeal \Drop"meal`\, Dropmele \Drop"mele`\, adv. [AS.
   drop-m[=ae]lum; dropa drop + m[=ae]l portion. Cf.
   Piecemeal.]
   By drops or small portions. [Obs.]
   [1913 Webster]

         Distilling dropmeal, a little at once.   --Holland.
   [1913 Webster]