242 DISEASES OF CATTLE. 



Avith the knife and sewed iij) 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 tlie 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 lim- 

 ited 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 j^assed as a loop 

 through a fine tube (like a teat tube open at each end) and introduced 

 into the teat. When this can not l)e 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. 



As a result of inflammation extending from without inward, a 

 gradual narrowing of the milk duct may occur from thickening and 

 narrowing of its lining membrane. This may be limited to a small 

 area near the lower end, or it may extend through the whole length 

 of the teat. The stream of milk becomes finer and finer until it 

 finally ceases altogether, and a firm cord is felt running through the 

 teat. If the constriction is only at the outlet, the teat may be seized 

 and distended by pressing the milk down into it from above, and an 

 incision may be made with a sharp penknife in two directions at right 

 angles to each other and directly in the original opening. The knife 

 should be first cleansed in boiling water. The opening may be kept 

 from closing by a dumb-bell shaped bougie of gutta-percha (PL 

 XXIV, fig. 5) or by the spring dilator. If the obstruction is more 

 extended it may be perforated by Liithi's perforating sound. (PL 

 XXIV, fig. 1a and 1b.) This is a steel wire with a ring at one end, 

 and at the other is screwed on to the wire a conical cap with sharp 

 cutting edges at the base, which scrapes away the thickened masses 

 of cells as it is drawn back. This may be passed again and again to 

 enlarge the passages sufficiently, and then the ])assage may be kept 

 open by wearing a long, dumb-bell bougie, a thick piece of carbolized 

 catgut, or a spring dilator. If the passage can not be sufficiently 

 opened with the sound it may be incised by the hidden bistoury. (PI. 

 XXIV, fig. 2.) This is a knife lying alongside a flattened protector 

 with smooth, rounded edges, but which can be projected to any re- 

 quired distance by a lever on the handle. The incisions are made in 

 four directions, as deep as may l)e necessary, and the walls then 

 can be held apart by the spring dilator until they heal. In case the 



