The Collaborative International Dictionary of English v.0.48:

Animalculism \An`i*mal"cu*lism\, n. [Cf. F. animalculisme.]
   1. (Biol.) The theory which seeks to explain certain
      physiological and pathological phenomena by means of
      animalcules.
      [1913 Webster]

   2. (Biol.) The theory that the spermatozo["o]n and not the
      ovum contains the whole of the embryo; spermatism; --
      opposed to ovism.
      [Webster 1913 Suppl.]