Spanish Flies (Cantharis vesicatoria). This once popular remedial agent has lost its position in modern medication. Its use came hand in hand with mediaeval medical cruelty, and was an heirloom of ancient heroic medication. Hippocrates (B. C. 375-400) valued cantharides in dropsy and also in amenorrhea, and it goes without question that a substance so heroic in its action would once have been popular in both domestic and professional American medication. Its use in erysipelas and as a plaster, and to "draw the nervous energy and the circulating fluid" to the surface, and "thus again relieve irritation and inflammation of internal parts," are relics of quite recent American medical authority, all writers in good reputation (Regular) commending it highly. At present, however, cantharis is in such disfavor as to make it a novelty for a cantharis plaster to be prescribed by a modern physician of any school, and to ignore its use is no longer a mark of heresy. This change from extreme popularity to practical disuse has come within the experience of this writer.