Acute Mammitis 943 



such a cow bring about an infection of her own udder, but with 

 her soiled tail she may convey the infection to another cow in an 

 adjacent stanchion, or the neighboring cow may strike her tail 

 against the soiled parts of the diseased animal, and thence carry 

 the infection to her own udder. 



There is frequently convincing clinical evidence that a milker 

 carries the infection to a healthy teat. He may get the infec- 

 tion upon his hands from an animal which is suffering from 

 mammitis, and may readily convey it to another teat of the same 

 udder, or, without washing his hands, may carry it farther and 

 deposit the infection upon the teats of a healthy cow, and induce 

 the disease. It is not essential that the milker should get the 

 infection from a diseased milk gland. He can as readily and 

 as seriously infect his hands by handling a putrid afterbirth, or 

 an aborted fetus, or an infected wound upon any animal, and, by 

 negligence or oversight, carry the infection to the udder of a 

 healthy cow. 



It has been suggested that, when cows lie down, straws from 

 their bedding may be pushed through the orifice into the milk cis- 

 tern and carry with them virulent and infectious material, and 

 there have probably been sufficient observations upon this point 

 to establish the fact that such infections really occur. Every 

 veterinarian in dairy practice has probably observed numerous 

 cases of infection by means of the milk tube. Iva3'men very 

 generally believe that they can meddle with the inside of a cow's 

 teat with the same degree of abandon with which they may 

 handle the outside, and many of them do not hesitate, upon the 

 least excuse, to insert a milk tube, a sound, a wire, a knitting 

 needle, or almost any implement, into the teat, and do not an- 

 ticipate therefrom any serious consequences. 



Thus, ■ in many ways infection of a virulent character may be 

 forced through, or find its entrance into, the milk cistern. 

 Once it has reached the milk cistern and milk canals, it is in a 

 favorable environment for growth. The infection may then ex- 

 tend according to virulence and the resistance of the tissues, 

 along the larger, and thence along the smaller milk ducts, and 

 may finally reach the milk acini and attack the secretory epithe- 

 lium of those structures, and produce any symptoms or patho- 

 logic conditions which the various forms of organisms are capa- 

 ble of inducing in such tissues. 



