animalculism

from The Century Dictionary.

• noun The theory that animalcules cause disease.
• noun The doctrine or theory of incasement in the male; spermism; spermatism. See incasement.
• noun Also called animalism.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Biol.) The theory which seeks to explain certain physiological and pathological phenomena by means of animalcules.
• noun (Biol.) The theory that the spermatozoön and not the ovum contains the whole of the embryo; spermatism; -- opposed to ovism.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun biology, archaic A theory seeking to explain certain physiological and pathological phenomena in terms of animalcules.