Segmentation Quotes (2 quotes)
In systemic searches for embryonic lethal mutants of Drosophila melanogaster we have identified 15 loci which when mutated alter the segmental patterns of the larva. These loci probably represent the majority of such genes in Drosophila. The phenotypes of the mutant embryos indicate that the process of segmentation involves at least three levels of spatial organization: the entire egg as developmental unit, a repeat unit with the length of two segments, and the individual segment.
[Co-author with American physiologist Eric Wieshaus (1947-)]
[Co-author with American physiologist Eric Wieshaus (1947-)]
'Mutations Affecting Segment Number and Polarity in Drosophila', Nature, 1980, 287, 795.
The extracellular genesis of cells in animals seemed to me, ever since the publication of the cell theory [of Schwann], just as unlikely as the spontaneous generation of organisms. These doubts produced my observations on the multiplication of blood cells by division in bird and mammalian embryos and on the division of muscle bundles in frog larvae. Since then I have continued these observations in frog larvae, where it is possible to follow the history of tissues back to segmentation.
'Ueber extracellulare Eutstehung thierischer Zelleu und üüber Vermehrung derselben durch Theilung', Archiv für Anatomie, Physiologie und Wissenschaftliche Medicin (1852), 1, 49-50. Quoted in Erwin H. Ackerknecht, Rudolf Virchow: Doctor Statesman Anthropologist (1953), 83-4.
In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.
(1987) -- 
