254 DISEASES OF CATTLE. 



01- end of a nail in the floor, with sudden and extreme changes of 

 weather, with overfeeding on rich albuminous food like cotton-seed, 

 beans, or peas, with indigestions, with sores on the teats, or with insuf- 

 ficient stripping of the udder in milking. In the period of full milk the 

 organ is so susceptible that any serious disturbance of the general 

 health is liable to fall upon the udder. 



The symptoms and mode of onset vary in different cases. When fol- 

 lowing exposure there is usually a violent shivering fit, with cold horns, 

 ears, tail, and limbs, and general_ereetion of the hair. This is succeeded 

 by a flush of heat (reaction) in which the horns, ears, and limbs become 

 unnaturally warm, and the gland swells up and becomes firm and solid 

 in one, two, three, or all four quarters. There is hot, dry muzzle, ele- 

 vated temperature, full, accelerated pulse, and excited breathing, 

 impaired or suspended appetite, and rumination with more or less cos- 

 tiveuess, suppression of urine, and a lessened yield of inilk, which may 

 be entirely suppressed in the affected quarter. 



In other cases the shivering escapes notice, the general disorder of 

 the system is little marked or conies on late, and the first observed sign 

 of illness is the firm swelling, heat, and tenderness of the bag. As the 

 inflammation increases and extends the hot, tender udder causes the 

 animal to straddle with its hind limbs, and when walking to halt on the 

 limb on that side. If the cow lies down it is on the unaffected side. 

 With the increase in intensity and the extension of the inflammation 

 the general fever manifests itself more prominently. In some instances 

 the connective tissue beneath the skin and between the lobules of the 

 gland is affected, and then the swelling is uniformly rounded and of 

 nearly the same consistency, pitting everywhere on pressure. In other 

 cases it primarily attacks the secreting tissue of the gland, and then 

 the swelling is more localized, and appears as hard, nodular masses in 

 the interior of the gland. This last is the usual form of inflammation 

 occurring from infection entering by the teats. 



In all cases, but especially in the last-named form, thennilk is sup- 

 pressed and replaced by a watery fluid colored with blood (sometimes 

 deeply), and mingled with masses of clotted casein. Later it becomes 

 white and purulent, and in many cases of an offensive odor. 



The course of the disease is sometimes so rapid and at others so slow 

 that no definite rule can be laid down. In two or three days, or from 

 that to the end of the week, the bag may soften, lose its heat and ten- 

 derness, and subside into the healthy condition, even resuming the 

 secretion of milk. The longer the inflammatory hardness continues 

 the greater the probability that its complete restoration will not be 

 effected. When a portion of the gland fails to be restored in this Avay, 

 and has its secretion arrested, it usually shrinks to a smaller size. 

 More commonly a greater amount of the inflammatory product remains 

 in the gland and develops into a solid fibrous mass, causing permanent 

 hardening (induration). In other cases, in place of the product of 



