THE GERM-PLASM THEORY 



It maintains that the development of the ovum to the perfect animal 

 is not really a new creation, but only an unfolding of invisible small 

 parts, which were already present in the ovum. It assumes that 

 the parts of the perfect organism are already preformed in the ovum, 

 and on this account it is called the ' Preformation Theory.' Bonnet 

 often speaks of the preformation of the perfect animal in the germ 

 as a 'miniature model/ although his conception of 'evolution' was 

 not really so crude as has been often alleged. He expressly 

 emphasized that this miniature model was not exactly like the 

 perfect animal, but consisted of 'elementary parts' only, which he 

 thought of as a net whose meshes were filled up during development 

 and by means of nutrition with an infinite number of other parts. 

 But after all, his conceptions, and those of his time generally, were 

 very far removed from the biological thinking of our own day, as 

 may perhaps be most readily understood when I mention that he 

 regarded death and decay as an 'involution,' as a folding Lack, 

 so to speak, by means of which all the parts gained though nutrition 

 were removed again, so that the net of the miniature model shrank 

 together to the invisible minuteness that it had in the ovum. So 

 it remained, he fancied, till it was reawakened at the resurrection, 

 using the term in the religious sense! He afterwards dropped 

 this fancy, because the objection was made to it that human beings 

 who had lost a leg or an arm in this life would necessarily be maimed 

 at the resurrection ! 



In Bonnet's time the facts of development were quite unknown, 

 and not even the stages of the development of the chick from the 

 egg had been observed. When this was afterwards don.- tic 

 prevalent theory of 'evolution' necessarily collapsed, for men saw 

 with their own eyes that a miniature model of the chick did not 

 gradually grow into visibility and ultimately into the young chick, 

 but that first of all parts showed themselves in the egg which bore 

 no resemblance at all to the chick, that these first rudiments were 

 then altered, and that through continual new formation- ami trans- 

 formations the chick finally appeared. Upon this K. von Wolff ba 

 his theory of ' Epigenesis,' or development through new formations 

 and transformations. He maintained that the doctrine of ' Evolutio 

 was false; that there is no miniature model invisibly contained within 

 the egg; but that from the simple egg-substance there arises, 

 through the agency of the formative powers inherent in it, a long 

 series of stages of development, of which each succeeding one is more 

 complex than the one before, until ultimately the perfect animal is 

 reached. 



