Commentary:

This story does nothing for some readers; for others it is terrifically successful and effective. One suspects that it depends on one's feelings about being deep underground and how active one's imagination is concerning that kind of isolation.

The phrase "fossil monster" (125) is telling, concerning attitudes about unfamiliar life forms. For the politics of the '30s, note the narrator's comment concerning an erroneous interpretation of "trouble with the men": "Higher wages? ... What they need is more patriotism" (130).

The horror in the tale probably derives less from the "science" -- the molecular physics of these dense "microscopic giants" -- and more from the eeriness of diminutive menace. Note that the creatures are compared with dolls and called "mannikin[s]" occasionally (138), so the "devil doll" principle may also apply, as might the fact that these things can blow away half your chest or rip your hand off (139).

Ernst, Paul. "The Microscopic Giants." 1936. Science Fiction Terror Tales. Ed. Groff Conklin. NY: Gnome Press Inc., 1955. 124-142.

"When Dolls Attack: A Filmography." Monsters. http://www.wsu.edu/~delahoyd/dolls.html.