The in vitro morphogenesis of the guinea pig egg cylinder.

The guinea pig embryo has been grown from the blastocyst to the egg cylinder stage in vitro. Moreover, histological, cytological and cytophotometrical studies have shown that the in vitro-derived egg cylinders closely resemble age-matched, in vivo embryos. In addition, constituent tissue layers were also isolated from the in vivo and the in vitro-derived egg cylinders. These were subsequently grown in culture and found to be, upon cytophotometrical study, similar in DNA content. Results thus obtained further support the idea that morphogenesis in culture paralleled normal development.