The sheath of omentum that forms about a long rubber tube left within the peritoneal cavity provides so efficient a barrier to ascending infection that such a tube can be employed for the permanent drainage of the common duct, whereas a short tube will regularly come away after a few days. A method is described whereby the total bile of a considerable number of dogs has been obtained in a sterile state during periods up to 3 months. Save for some anemia, the animals remained in good health throughout. The method has obvious uses in connection with the collection of other secretions.