"The gaunt thing with no organs creeps along the streets"If something has no organs then it is dead,creeps along the streets means un-detected; death "creeps" up on you, it is around every corner.
"she will be the great witch of euro-american legend who sucked the life from some unknown nigger whose name will be known but whose substance will not ever even by him who is dead in a pile of dopeskin"I think "Witch" in this context means a mechanism of death, the person will not have ever known their "substance" or addiction. "Dopeskin" can give the impression of referencing to drugs. "..full of American holes and a monkey on his back" "American holes" to me means the tracks that are left on a person after continual drug use and the "monkey" on his back is the guilt from the addiction.
On the other hand I believe there are some references to war considering Baraka's previous war experiences.
On the other hand I believe there are some references to war considering Baraka's previous war experiences.