t
this worke of generation, there needeth not be supposed a forming
vertue ... of an unknowne power and operation.... Yet, in
discourse, for conveniency and shortnesse of expression we shall
not quite banish that terme from all commerce with us; so that what
we meane by it, be rightly understood; which is, the complexe,
assemblement, or chayne of all the causes, that concurre to produce
this effect; as they are sett on foote, to this end by the great
Architect and Moderatour of them, God Almighty, whose instrument
Nature is.[11]

Digby's general theory thus represents a strange mixture of epigenesis
and pangenesis, and is not entirely devoid of "virtues." It is, however,
a bold attempt to explain embryonic development in terms commensurate
with his time, and it embodies the same optimistic belief that the
mechanism of embryogenesis lay accessible to man's reason and logical
faculties that similarly led Descartes and Gassendi to comprehensive
interpretations of embryonic development comprising a maximum of logic
and minimum of observations.

The traditionalist reaction to the attack upon treasured and
intellectually comfortable interpretations of development was not slow
to set in. A year after the appearance of Digby's _Nature of Bodies_,
Alexander Ross published a treatise with a title indicating its goals
and content: _The Philosophicall Touch-Stone; or Observations upon Sir
Kenelm Digbie's Discourses of the nature of Bodies, and of the
reasonable Soule: In which his erroneous Paradoxes are refuted, the
Truth, and Aristotelian Philosophy vindicated, the immortality of mans
Soule briefly, but sufficiently proved_.[12] Ross supports the Galenist
tradition that the liver, not, as Digby claimed, the heart, forms first
in development. It can be no other way, he says, since the blood is the
source of nourishment and the liver is necessary for formation of the
blood. Furthermore, he contends, "the seed is no part of the ... aliment
of the body ... the seed is the quintessence of the blood."[13] Ross is
an epigeneticist, to be sure, but so was Aristotle, and Ross prefers to
maintain the supremacy of logic and the concepts of the Aristotelian
tradition as a guide to the interpretation of development.

In 1651, Nathaniel Highmore, a physician at Sherborne in Dorset,
published _The History of Generation_, which, he informs us, is an
answer to the opinions expressed by Digby in _The