The purpose of this paper is to analyze the various factors
which contributed toward the development of what has often
been called the "theory of preformation." The eighteenth-century
version of this theory, popularized by Bonnet, Hailer, and others,
centered upon the concept of emboitement, the belief that the
generation of new organisms was nothing more than the expansion
of miniatures which had existed since the first creation
of the universe, stored up one generation within another. This
first became popular toward the end of the seventeenth century,
when many different factors combined to promote its development.
Some of these factors have only an indirect relationship to
emboitement itself, but have often been confused with it; the
following discussion will attempt to distinguish the various
positions supported by the embryologists of the late seventeenth
century, and to assess their contributions to the growth of the
theory which became so popular in the following century.