Final answer:
Marlow likely feels a mix of uneasiness and revulsion when he hears the tribesmen howl and watches them dance, experiencing the intensity of being in an unfamiliar and alien world.
Step-by-step explanation:
In the context of Joseph Conrad's Heart of Darkness, Marlow's feelings upon hearing the tribesmen howl and watching them dance is not one of excitement or joy. Instead, Marlow experiences a complex mix of emotions, including uneasiness, fear, and a profound sense of being an outsider in an unfamiliar world. The provided references do not directly align with Conrad's novel, but they do touch on the idea that music can communicate universal emotions such as happiness, sadness, and fear, as well as how observing suffering can evoke pity and fear. Based on the understanding of these general human reactions to circumstances and assuming a standard response, it would be likely that Marlow's experience is closer to fear and revulsion in such an intense and alien situation.