Under unhealthy conditions of the gland or milk ducts clots of casein form which, pressed clear of most of their liquid and rolled into rounded masses, may block the passage. They can be moved up and down by manipulation of the teat, and if they can not be pressed out they may be extracted by using the spring teat dilator (Pl. XXIV, fig. 3), being held surrounded by its three limbs. Before extraction is attempted an ounce of almond oil, boiled, should be injected into the teat. TEAT BLOCKED BY CALCULUS. When the calcareous matter of the milk has been precipitated in the form of a smooth, rounded stone, a rough, conglomerated concretion, or a fine, sandlike dÈbris, it may cause obstruction and irritation. These bodies are felt to be much harder than those formed by casein, and the milk usually contains gritty particles. Extraction may be attempted, in the case of the finely divided gritty matter, by simple milking or with the spring dilator (Pl. XXIV, fig. 3) in the case of the larger masses. Should this fail the teat may be laid open with the knife and sewed up again or closed with collodion, but such an operation is best deferred until the cow is dry. TEAT BLOCKED BY A WARTY OR OTHER GROWTH INSIDE. In this case the obstruction may be near the orifice of the teat or farther up, and the solid mass is not movable up and down with the same freedom as are concretions and calculi. The movement is limited by the elasticity of the inner membrane of the teat from which it grows, and is somewhat freer in certain cases because the growth has become loose and hangs by a narrow neck. In the case of the looser growths they may be snared by a fine, spring wire passed as a loop through a fine tube (like a teat tube open at each end) and introduced into the teat. When this can not be done, the only resort is to cut in and excise it while the cow is dry. THICKENING OF THE MUCOUS MEMBRANE AND CLOSURE OF THE MILK DUCT.