reported that "I arrived at the prison and found that noble group of martyrs, as they then marched up and down in your heart and with their war song 'March of the Women' sang, while the composer was watching benevolently from a high window and with the bacchanalian energy tact with a toothbrush beat." My understanding is she was leaning out a prison window, conducting a group of women protesting in front of the prison, using a toothbrush as her baton. (Is that not a fantastic visual image?) Her work is still available for purchase today. Her autobiography, "Impressions That Remained - Memoirs Of Ethel Smyth" is said to be one great. (I haven't read it, but I'm intrigued.)
If you'd like to hear "The March of the Women," here's a video (well, photo slideshow) set to the Rainbow Chorus singing it in 2009.