Spemann and his coworkers grafted a piece of prospective neutral ectoderm from an early Gastule stage donor embryo in newt genus triturus intoa region of host embryo where Belly skin should develop
Answers
The main work of Spemann and his colleagues was to investigate the nervous system of the peripheral foetus which was found in the ectoderm of the host tissue.
Here, he is trying really hard to metamorphose the implanted tissue from the host tissue.
Until he has concentrated only in the transfer from one to another in the same foetus, after that he used only two embryos which are of the same age from different species.
As a result, he has chosen implant as newts Triton cristates which is almost colourless and host as Triton taeniatus which is highly pigmented. They both are different species.
Finally, he found that the grafts are dispersed below the gastrula to form mesodermal elements in the second foetus. Here, the ectoderm of the host was influenced to form the host material.