Stricture or Atresia of the Teats 995 



teat, it is found that the milk descends slowly or not at all into 

 the teat, but, if it once descends into the milk cistern, 

 is easily pressed out. When the cistern is emptied, however, it 

 is slow in refilling, and consequently the milking process is ex- 

 ceedingly tedious. In those cases of stricture where the upper part 

 of the cistern is completely closed, the milk may readily be felt 

 in the milk canals above, pressing down upon the obstruction, 

 while the teat remains empty. Examining closely the base of 

 the teat, one usually finds in the central portion of the teat base 

 a hard, firm nodule, irregularly spherical in form and varying in 

 size from }i io }( inch in diameter 



The pathologic processes which lead to a narrowing of the teat 

 canal are usually referred to some traumatism, involving the epi- 

 thelium, the mucous membrane, or the sub-mucosa of the teat 

 canal. Lesions of this character are assumed to follow such in- 

 juries as treads, blows or rough milking. Following these 

 injuries, hemorrhages may occur into the sub-mucosa, ac- 

 companied by exudation into the surrounding tissues. After the 

 wounded parts have become infected and inflamed, and have later 

 healed, there remains a cicatricial thickening and induration of 

 the epithelium and sub-mucous tissue. In some cases the thick- 

 ening involves almost the entire length of the teat canal, and ex- 

 tends completely around it. 



In our observation, most of the cases of stricture and atresia 

 of the teat occur at the base, without any history whatever of 

 traumatism or preceding mammitis. We frequently observe the 

 slow formation of a nodular enlargement of a very firm character 

 at the base of the teat, usually almost directly in its center, at 

 the point of entrance of the milk canals into the cistern. 



As the nodule begins to form, the milker first observes that 

 the milking process is retarded. The milk is readily pressed out 

 from the well-filled cistern through the teat orifice, but the cistern 

 does not promptly refill. After waiting for a time, the cistern 

 again fills and the teat becomes distended. 



Slowly and insidiously the difiiculty in milking increases, and 

 careful palpation reveals a firm hard nodule centrally located in 

 the base of the teat. At first it appears about )4 inch or less in 

 diameter, very firm, painless. It grows some, but does not attain 

 a large size, usually not more than }( inch. 



