268 . BIOLOGICAL LECTURES. 



tion of fixed types or forms. It culminated in that finished 

 theory of predelineation in embryonic development known as 

 e^nboiternent} This was, in reality, the very negation of all 

 development, since the theory held that all the individuals of 

 a species had been created simultaneously for all time.^ In the 

 forcible language of the last century. Eve's ovary contained 

 the compressed and diminutive germs of all coming human 

 beings incapsulated one within the other. Such a theory 

 could arise only from overestimation of the definitive form 

 attained through development, and an underestimation of the 

 changes undergone by the egg during its development. The 

 typical adult form usurped the theorist's attention, and the 

 elaborate process whereby the type was gradually realized 

 shrunk to a mere unshelling and subsequent growth in size 

 of the next individual in order in the incapsulated series. 



For the theory of cmbotteviettt the creation not only of every 

 species, but of every individual organism on our planet, by a 

 single preadamite fiat, was a necessary postulate. The rival 

 theory, epigenesis, implied in the cosmology of Heraclitus and 

 easily traceable to Aristotle, starts with a simple form of 

 unorganized matter, which through the agency of certain forces 

 undergoes the complicated changes that finally result in the 

 adult living organism. The homogeneous becomes the hetero- 

 geneous. The creation of new organisms is no longer con- 

 ceived as having taken place once for all in a remote and 

 inscrutable past, but as taking place everywhere and at all 

 times. An exaggeration of epigenesis is spontaneous genera- 



1 Passages which show the close genetic relationship of Neo-Platonic and 

 Christian thought on the subject of creation are not infrequent in the writings of 

 the Church Fathers. The following quotations from Augustine clearly express the 

 idea of eniboitement : " Sicut autem in ipso grano invisibiUter erant omnia simul, 

 quse per tempora in arborem surgerent, ita ipse mundus cogitandus est, cum Deus 

 simul omnia creavit, habuisse simul omnia, quce in illo et cum illo facta sunt, 

 quando factus est dies: non solum coelum cum sole et luna et sideribus . . . sed 

 etiam ilia quae aqua et terra produxit, potentialiter atque causaliter priusquam per 

 temporum moras ita exorentur, quomodo nobis jam nota sunt in eis operibus, 

 qu3c Deus usque nunc operatur." De Genesi ad lit., v, 45. " Omnium quippe 

 rerum quce corporaliter visibiliterque nascuntur, occulta qu^dam semina in istis 

 corporis mundi hujus elementis latent." De Trinitate, iii, 8. 



2 " Qui igitur systemata praedelineationis tradunt, generationem non explicant, 

 sed, earn non dari, affirmant." C. F. Wolff, Theoria Generationis, 1759, p. 5. 



