Germ layer origin and mitotic potentiality of regenerating tissues iuClymenella torquata

Summary and Conclusion

Mitotic activity is enhanced by sulfhydryl and held back by its sub-oxidized derivative in all the three chief germ layer derivatives of regeneratingClymenella torquata.

Thus, here as elsewhere, growth by increase in cell number is found to be regulated by the naturally occurring essential chemical equilibrium comprised of these chemical groups.

The degree of enhancement of mitotic activity by sulfhydryl differed in the three types of growing tissue. This experimental demonstration of the existence of an inherent difference in mitotic potentiality allows the inference to be drawn that relative proliferation intensity has played an important rôle in evolution.

The mesodermal derivative exhibited the greatest mitotic potentiality. In this property lies, in significant part, an explanation for the greater diversity of differentiated mesodermal end-products.

The experiments here reported were done byDorothy Wall Hammett andGeorgia Brawner. The sections were made byNevart Chatalbash. The unstinted assistance of these workers is truly appreciated as is the everlasting support of DoctorStanley P. Reimann, without which this work could not have been accomplished.