126 Facts Compelling Us to Reject Pre formation 



Everybody knows the peculiar static structure of bone. 

 Substance becomes accumulated in bone at the points of 

 greatest pressure, and attains thus its best possible utiliza- 

 tion. Now it is known, as J. Wolff discovered and as 

 Kastor, Martiny and J. Rabe have confirmed, that similar 

 structures are formed also in quite new and abnormal 

 circumstances in connection with new static conditions, 

 for example, in bones broken and reset at an angle. 

 "From this it follows," says Roux, "that these forma- 

 tions do not need to be fixed and inherited, but arise of 

 themselves whenever the conditions exist. As the static 

 structure of bones is developed in a clearly recognizable 

 form only after the first years of life, one can not say 

 anything of the necessarily hereditary transmission of 

 it, without special researches upon this point." 92 



Teratogenesis in general, both natural and artificial, 

 is quite opposed to preformation. It denotes that the 

 organism, at any rate while it is still in process of devel- 

 opment, can adapt itself to exceptional conditions which 

 are quite different from the normal. And it accom- 

 plishes this by producing abnormal formations whose 

 development must consequently be due only to a process 

 of epigenetic nature, and cannot be of preformistic 

 nature. 



Let us consider one of the simplest examples. In 

 the hemiteratic spina bifida, the spinal opening is ordi- 

 narily covered over by a layer consisting of fibrous 

 tissue like that of scars, which in some cases takes on 

 all the characters of the skin. Then the spinal opening 

 is not visible from the outside. But when the spinal 

 opening is in the lumbar region it is not rare for a 



* 2 Roux : Der Kainpf der Teile im Organismus. P. 28. 



