SUMMARY A method of transplanting a part of the pancreas into an exteriorized carotid artery—jugular vein loop in the neck of the sheep is described. Glucose and butyrate solutions were infused directly into the transplanted pancreas and shown to be powerful direct stimuli of insulin secretion by the pancreatic transplant. Patterns of insulin secretion during prolonged infusions of glucose and butyrate solutions into the pancreatic transplant are described. One of the sheep described here died 5 months after the transplantation. The other three sheep are all surviving in healthy condition 9, 12 and 18 months respectively, after the transplantation. The transplants of these three sheep continue to secrete insulin.