DISEASES FOLLOWING PARTURITION. 241 



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 concre- 

 tion, or a fine, sand-like debris, it may cause obstruction and irrita- 

 tion. These bodies are felt to be much harder than those formed by 

 casein, and the milk usually contains gritty particles. Extraction 

 may be attempted by simple milking in the case of the finely divided 

 gritty matter, or with the spring dilator (PI. 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 

 higher 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 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. 



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 Lflthi's perforating sound. (PI. XXIV, fig. 

 la and 15.) 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 sufficiently 



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