A Considerable amount of work has been done on the growth and regeneration of the adult mammal liver and theories of liver growth control have been put forward, the most far-reaching of which was advanced by Glinos (1958). According to this theory, the growth of the liver is regulated by a feed-back mechanism, involving diffusible chemical substances secreted into the blood by the liver itself. The higher the concentration of the substances in circulation, the less will be the rate of liver growth.
Much descriptive work has been done on the growth of embryonic chick organs (Romanoff, 1960), but none on the problem of growth control of the liver. It is possible that the postulated feed-back mechanism of liver growth control in the adult rat also operates in the chick embryo during development. But there is hardly any evidence for this.