Technique for repeated collection of blood that has just perfused the pineal gland of sheep.

A long catheter was inserted into the superior sagittal sinus of sheep and was maneuvered to the level of the rectus sinus. The catheter was then secured to the head, neck, and shoulder of the animal. The distal end of the catheter was connected to a 3-way valve through which blood samples were collected and heparin was injected. Blood loss during surgery was minimal; recovery was quick and complete. The simple surgical technique enabled the collection of blood that has just perfused the pineal gland.