ixt];rxal STKUCTUR1-: OF cows ui)iir;R 25 



of this opening, or at the end of the teat, there is a sphincter 

 niu>cle. Avhich in some cases is drawn up \"er}- tight, while in 

 other instances it is so loose that it Avill not prevent the millc from 

 escaping. In case the mu.-cle is so tight that the milk can be 

 drawn only with dihicult}', it ma>' be relaxed a trifle b\- inserting 

 a small, smcjoth wooden plug. This will usualh" dilate the open- 

 ing sufhcienth", st") that the milk ma}' be drawn with C(Jmparati^"e 

 ease. In some instances this mu^cle is so tight that it is necessary 

 t<j relax it b}' the use of a sharp knife. This, howcAx-r, should be 

 done Avith surgical skill; otherwise the whole muscle is likel}" to be 

 so injured as tcj cause the milk to leak aAva}" at all times. 



The upper part of this canal in the teat C(jnnect,-- Avith what 

 is called the milk-reserA'oir, The size of thi.-- reser\-oir ^■arie.■^ in 

 dilterent cows. The aA'erage capacit}" of this milk-cistern i^ 

 about one pint. The opening from thi.> reserA'oir into the teat 

 is aljfj guarded with a nm,->cle, (jAT-r this mu.-^cle the cow has 

 little control; (Ax-r the muscle at the lower end of the teat she 

 has no control whatewr. 



Opening into the sides and top of this reserA^oir are a large 

 number of tubes, which are called milk-ducts, The.-^e milk-ducts 

 extend from the reser^-oir uj) into the milk-gland. The\" radiate 

 in all directions, diA'ide and subdiA'ide, so as tcj form a \er\- large 

 number of small tubes. These milk-ducts are >urrounded with 

 hbrous muscular ti.^.--ue, ner\-es, and blood-A'es>eI.-, The\' are all 

 guarded b}- a special muscle at the junction with the main milk- 

 ducts, from which the}' radiate. These muscles are so inti- 

 matel}' connected with the nerA'es and muscular s}'stem of the 

 cow that she is able to open anrl close them at will. There are 

 \'ery few cows that are not able to hold U}> their milk during 

 ncr^'ous and exciting periods. It is a coimiion occurrence for a 

 n:iilker to get onl}- a small part of the miUc from a cow; this small 

 amount is the portion which is present in the teat and milk- 

 reservoir. Some cows are able to hold up this milk also, but the 

 majoritv of cows cann(jt perfecth" control the muscle \\'hich 

 guards the entrance to the teat. The imilk which is present in 

 the milk-ducts and which has to pass through these junctions 

 referred to above can be held up by most cows at will. 



