126 Facts Compelling Us to Reject Preformation 
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.” % 
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 
**Roux: Der Kampf der Teile im Organismus. P. 28. 
