animalculism
noun
an·i·mal·cu·lism
-kyəˌlizəm
plural -s
1
: a former theory in biology: various obscure physiological and pathological phenomena are caused by the activities of minute invisible animals
2
: a former theory in biology: the spermatozoon contains the whole embryo in miniature compare ovism
Word History
First Known Use
1845, in the meaning defined at sense 1