144 EMBRYOLOGY IN THE SEVENTEENTH [pt. ii 



designe begun. But the other way is when the matter is both made 

 and receiveth its form at the same time. ... So Hkewise in the Genera- 

 tion of Animals, some are formed and transfigured out of matter 

 already concocted and grown and all the parts are made and dis- 

 tinguished together per metamorphosin, by a metamorphosis, so 

 that a complete animal is the result of that generation; but some 

 again, having one part made before another, are afterwards nourished, 

 augmented, and formed out of the same matter, that is, they have 

 parts, whereof some are before, and some after, other, and at the 

 same time, are both formed, and grow. . . . These we say are made 

 per epigenesin, by a post-generation, or after-production, that is 

 to say, by degrees, part after part, and this is more properly called 

 a Generation, than the former. . . . The perfect animals, which have 

 blood, are made by Epigenesis, or superaddition of parts, and do 

 grow, and attain their just future or ciKfir} after they are born. . . . An 

 animal produced by Epigenesis, attracts, prepares, concocts, and 

 applies, the Matter at the same time, and is at the same time formed, 

 and augmented.. . .Wherefore Fabricius did erroniously seek after 

 the Matter of the chicken (as it were some distinct part of the egg 

 which went to the imbodying of the chicken) as though the genera- 

 tion of the chicken were effected by a Metamorphosis, or trans- 

 figuration of some collected lump or mass, and that all the parts of 

 the body, at least the Principall parts, were wrought off at a heat 

 or (as himselfe speaks) did arise and were corporated out of the 

 same Matter." Nothing could be more plain than Harvey's teaching 

 on epigenesis, so that he has precedence over Caspar Wolff on this 

 matter. 



On the relation between growth and differentiation Harvey has 

 some valuable things to say. The term "nutrition" he restricted to 

 that which replaces existent structures, and the term "augmenta- 

 tion" or "increment" to that which contributes something new. That 

 process which led to greater diversity of form and complexity of shape 

 he called "formation" or "framing". "For though the head of the 

 Chicken, and the rest of its Trunck or Corporature (being first of 

 a similar constitution) do resemble a Mucus or soft glewey substance; 

 out of which afterwards all the parts are framed in their order; yet 

 by the same Operatour they are together made and augmented, and 

 as the substance resembling glew doth grow, so are the parts dis- 

 tinguished. Namely they are generated, altered, and formed at once, 



