Transplantation et Régénération chez la Planaire Dendrocoelum lacteum

Abstract

ABSTRACT A graft of prepharyngeal origin, implanted behind the mouth, tends to dominate the posterior fragment obtained by postbuccal section. If this section runs through the graft, the latter regenerates a head at its free anterior border while the host edges undergo a regulation of form. After a similar section, the graft having previously been irradiated with X rays, the postpharyngeal host region provides the graft with the necessary material for regeneration and the final result is identical with the preceding one, except that regeneration is delayed for about twelve days during which the healthy neoblasts are migrating across the irradiated graft. If the section goes between mouth and graft, no regeneration is possible at the level of section. The graft bulges dorsally, develops eyes, and its movements draw the posterior part along. A graft of postpharyngeal origin, implanted at the anterior level of a decapitated and X-irradiated worm, supplies the host with its own healthy cells, but it remains unable to perform any head regeneration from a free border running through itself.