98o Veterinary Obstetrics 



the bitch, edema of the mammae may occur at about the normal 

 time for parturition, after the disappearance of estrum without 

 impregnation. In these instances it seems that the functional 

 activity of the glands becomes aroused without pregnancy having 

 taken place at all, as the result of some organic sympathy be- 

 tween the two parts of the generative system. 



We have also observed such edema of the udder, in the non- 

 pregnant mare mule, accompanied later by the active secretion, 

 of milk. In these cases the edema was related to the functional 

 activity of the uterus and ovaries, and occurred during the breed- 

 ing season only. 



In the cow, when for any reason the milk canals or the teats 

 become blocked so that the milk cannot escape, there occurs a 

 great distension of the gland, by the accumulation of milk within 

 its canals, until the pressure within its cavity attains such a de- 

 gree that the further secretion of milk is stopped. This condi- 

 tion of over-distension brings about an edema of the gland, 

 accompanied by retrograde changes in the milk and its final 

 resorption, followed by atrophy of the gland. 



When the young is removed from the mother while lactation 

 is still active, a similar edema results because of the over-disten- 

 sion of the gland. This very frequently leads to infection, be- 

 cause the orifice to the teat is open, which permits the invasion 

 of micro-organisms. Should the gland escape infection, the 

 changes taking place pursue the same course as in those instances 

 where the teat orifice is blocked and infection prevented. 



The symptoms consist essentially of a gradually increasing 

 tension of the gland, which may be more or less painful and may 

 involve a quarter or half or the entire gland, while the edema 

 may extend forward anterior to the mammae, or upward and 

 backward to the region of the perineum. 



The temperature is little or not at all elevated, and the secre- 

 tions from the gland are not materially altered from the normal. 



The anatomical conditions, in cases of edema or congestion of 

 the udder, consist essentially of vascular engorgement and con- 

 gestion of the inter- glandular connective tissue. Unless the 

 edema leads to infection, the disease pursues a favorable course 

 and ends in spontaneous recovery after a few days. Especially 

 is this true of the engorgement of the gland just prior to 

 parturition. 



