PLATE 3. 



COWS UDDER. 



^ 



Section of Udder of Cow. 



The ssstion shows the anterior quarter (n) separate 1 from the pos- 

 terior quarter (6) by a septum ((?). At the top of the posterior quarter is 

 situated a large lymph glanl ( f). Near the centre of each gland anl at the 

 bxse of the teat there is a single large lactiferous sinus or milk cistern ((/), 

 which is the general confluent of all the lactiferous ducts (c, c), an 1 opens 

 externally through the teat by a single excretory canal (c). This canal is 

 widest at its commencement and narrow at its termination at the end of 

 the teat. The walls of the latter are very thick, elastic, anl retractile. 





rJPt-;/?*;: 



Section of Gland Lobule. 



A, Lobule of mammae filled with milk. B, Milk 

 globules. C, Colostrum — (a) cell with a visible nucleus, 

 (6) cells firom which nucleus has disappeared. 



Section of Teat. ] 



a, a, Principal lactiferous ducts ; b, lac- 

 tiferous sinus ; c, c, acini ; d, elastic or 

 dartoid tissue ; e, oritice of teat. 



The dartoid tissue acts as a sphincter, 

 preventing the passive escape of the milk 

 from the orifices of the excretorj- ducts. 

 If a small cannula be inssrted beyond the 

 orifice, the secretion immediately flows. 



From Fleming's Vettrinanj Obstetrics.] 



[Fuce page lH. 



