Miss Martha somehow thinks that her simple act of kindness—adding butter to Blumberger's stale loaves of bread—will make her regular customer want to share a meal with her one evening instead of eating alone in his cramped little garret. In that sense, she's trying to bewitch Blumberger by adding something to his loaves, almost like a magic elixir. Miss Martha also applies a strange compound of quince seed and borax to her complexion to make herself appear younger. There's something weird and witchy about this; it's as if she's using a magic potion, the kind that keeps you in a state of eternal youth. But if Miss Martha is some kind of a witch, then she's not a very good one, for her attempts to attract the attention of the gruff architectural draftsman prove ultimately unsuccessful.
O. Henry was a master of irony. Almost all of his short stories dealt with the ironies of life. This is also true of the story "Witches Loaves." The title is ironic for two reasons. One is that he alludes to Miss Martha using a recipe of "a mysterious compound of quince seeds and borax," which was supposedly for her complexion. Yet, he leaves the impression that it is also something that a wise woman, or witch, who might be versed in herbal lore, might do to create a love spell.
The second, and more ironic use of the title indicates that the man, Blumberger, calling her an "old cat" when she inadvertently ruins his drawings because her romantic fancy of him as a starving artist prompted her to add butter to his stale bread, considers her the equivalent of a witch who put an evil spell on him and destroyed his work.
Perhaps the German draftsman perceived those two particular loaves of bread as "witches' loaves" because they destroyed his plans, and he was, therefore, cursed by them. In other words, they were like the brew of a witch in that they contained powers to destroy.
The title of O. Henry's painful short story "Witches' Loves" has several meanings, each of which dramatizes a part of the story. The first is that at times, "Witches' ___" (fill in the blank) is used as an invective against someone one is really agnry with or toward something one is really angry about. The artist was certainly really angry about what those...those...those witches' loves did to his drafting plans...really angry.
The second and third meanings are closely linked. You recall that Miss Martha prepared a mysterious brew of quince and borax in the kitchen, and the narrator says that "Ever so many people use it for the complexion." Upon consulting Practical Druggist and Pharmaceutical Review of Reviews, Volumes 25-28, you find that various quince borax recipies for bars--or loves--of creams or soaps are used for beauty treatments.
In a metaphorical sense, Miss Martha can be said to be brewing up witches' loves with witchly mysterious recipies for purposes of romantic witchery. In another metaphor, Miss Martha's beauty treatment loaves and her doctored--or bewitched--loves of bread are intended as magic potions to capture the affections of the lonely artist who subsists on stale bread--or so she thinks.
I don't know if we know for sure why O. Henry called this story Witches Loaves. What we do know is that he chose the titles for his stories very carefully and they all represented an important idea in the story itself.
Perhaps O. Henry was thinking of another story when he wrote this - the fairy tale of Hansel and Gretel. In folklore, witches often used food to lure people into their traps. The witch in Snow White used an apple, the witch in Hansel and Gretel used candy. In this story, the "witch" is Miss Martha. Why is she a witch? She thinks she is a kind woman who feels sorry for a starving artist. Week after week, she eats rich food but never offers any to her customer. She wishes he would notice her, but she tells herself he is too proud. She does everything she can to entice him into a conversation with her. She hangs up a painting, she wears a fancy dress, she puts goop on her face to make her skin look good. Finally, she uses food - she puts butter into the two stale loaves of bread, thinking she is giving her poor starving artist customer a treat. Now he will think of her when he eats the stale bread. Perhaps he will ask her to tea. Alas. Her plan backfires. He has been buying the bread to use as an eraser for his drawings. He is a draftsman. The buttered bread has ruined his drawings. In typical O. Henry style, there is a surprise ending. The loaves turn from something good into something "witchy".
Of course, the title could mean something totally different, but that is my idea.
Maybe some other teacher has some specific information, but when I checked, I could not find anything so it is up to us to figure it out. What do you think?