ABSTRACT
Because neocortex appeared to be too fragile to survive transplantation, Ranson (1909, 1914) chose to introduce the second cervical gangion taken from 1-week-old rats to the cortex of 1-month-old rats. Not only did he observe surviving neurons within the grafted tissue, but application of silver stains indicated that axons ran throughout the graft at least as far as the graft-host interface. This work influenced Dunn (1917), who returned to the neocortex and was the first to publish convincing evidence that transplanted brain tissue could survive. She grafted pieces of neocortex taken from 9-to 10-day-old neonatal rats into lesion cavities made in litter mates and found that in 90f 44 recipient rats small amounts of transplant tissue containing viable neurons survived for as much as 200 days. Dunn also reported a second observation of importance to neurotransplantation research. The grafts that survived had been placed in the deepest cortical wounds and had come into contact with the choroid plexus of the lateral ventricles. This contact permitted rapid vascularization of the transplants (Dunn, 1917).
