a procedure for the continuous collection of oviduct fluid from the cow. Cannulation of the oviduct was accomplished with a single silastic cannula held in the oviduct by two collars sutured to the ovarian end of the oviduct. Numerous oviducal fluid collection systems have been used with varying degrees of success. Hamner & Fox (1969) reviewed collection techniques used in several species including the sheep, pig, monkey and rabbit. Yoshinaga, Mahoney & Pincus (1971) reported continuous collection from both oviducts. The animals used in this study were nulliparous dairy heifers (10 to 20 months of age) which were observed in oestrus at least once before surgery. All operations were performed at mid-cycle under either local anaesthesia (Neurothesia) or inhalation general anaesthesia (Fluothane and N20). Following laparotomy in the region of the left paralumbar fossa, the re¬ productive tract was brought to the opening for observation and cannulation. Under general anaesthesia, it was possible to obtain a fuller exposure of the reproductive tract through the flank incision. A double-walled silastic (Dow Corning Corporation, Midland, Michigan) cannula sealed together with silicone adhesive (Medical Adhesive-Silicone Type A, Dow Corning) was threaded into and sutured within the fimbria of the left oviduct with 5-0 silk. Several sutures through the silicone adhesive bleb and the adjoining tissue as well as two to four sutures around the fimbria and cannula were used to hold the device in place. The overall length of the cannula was 46 to 60 cm depending on the size of the animal. The utero¬ tubal junction was ligated with a single 3-0 suture to prevent flow of secretions into the uterus or backflow from the uterus into the oviduct. Care was taken to include only the oviduct with this ligature so that no sizeable blood vessels were occluded. Since both ends of the oviduct were sealed off, any fluids col¬ lected were either secreted by cells of the oviduct or by transudation from the