The Embryo at the Wound 45
ribosomes (the cell's protein-factory organelles) to make the particular
proteins that distinguish a nerve cell, for example, from a muscle or
There's a superficial similarity between this genetic mechanism and
the old determiner theory. The crucial difference is that, instead of de-
terminers being segregated until only one remains in each cell, the genes
are repressed until only one set remains active in each cell. However, the
entire genetic blueprint is carried by every cell nucleus.
Science is a bit like the ancient Egyptian religion, which never threw
old gods away but only tacked them onto newer deities until a bizarre
hodgepodge developed. For some strange reason, science is equally reluc-
tant to discard worn-out theories, and, even though there was absolutely
no evidencc to support it, one of Weismann's ideas was swallowed
whole