The Collaborative International Dictionary of English v.0.48:

Microcosmic \Mi`cro*cos"mic\, Microcosmical \Mi`cro*cos"mic*al\,
   a. [Cf. F. microcosmique.]
   Of or pertaining to the microcosm.
   [1913 Webster]

   Microcosmic salt (Chem.), a white crystalline substance
      obtained by mixing solutions of sodium phosphate and
      ammonium phosphate, and also called
      hydric-sodic-ammonic-phosphate. It is a powerful flux,
      and is used as a substitute for borax as a blowpipe
      reagent in testing for the metallic oxides. Originally
      obtained by the alchemists from human urine, and called
      sal microcosmicum.
      [1913 Webster]

WordNet (r) 3.0 (2006):

microcosmic
    adj 1: relating to or characteristic of a microcosm; "the
           microcosmic world of business"

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "microcosmic":
   atomic, corpuscular, embryonic, evanescent, germinal, granular,
   impalpable, imperceptible, imponderable, inappreciable,
   indiscernible, infinitesimal, intangible, invisible, microscopic,
   molecular, subatomic, tenuous, thin, ultramicroscopic, unseeable