DISEASES OP THE BLOOD. 159 



four days. Vaccinia is not a severe affection ; it renders 

 the milk unfit for food, and diminishes the supply jpro 

 tem.y though febrile conditions seldom run very high, and 

 present nothing very special in their characters. The 

 first manifestation of local lesion is redness, at first dif- 

 fused, subsequently circumscribed, in patches over the 

 mammary gland and teats, also pain and general swelling. 

 When the parts are reddened, small hard nodules appear 

 and increase in size until they attain about the size of a 

 sixpence. This is the papular stage ; next comes the vesi- 

 cular. A serous accumulation extends from the centre, ren- 

 dering the vesicae bluish, though they are still surrounded 

 by a congested ring (areola). The central point, however, 

 does not project, but remains somewhat slightly bound to 

 the corium. Consequently the vesica has an umbilicated 

 appearance. About the eighth or tenth day these vesicas 

 attain their maximum development. Then comes the 

 pustular stage, which lasts for two or three days, and then 

 the contents of the pustule, if not set free by rupture, 

 become absorbed, and a peculiar brown scab remains 

 (siccative stage) for a varying length of time. Vaccine 

 lymph should be collected only from the matured vesicw, 

 and should contain neither pus nor blood, neither should 

 it give the slightest evidence of putridity or milkiness. 

 An attack of cow-pox generally extends over several 

 weeks ; the disease prevails especially in the spring, and 

 in certain parts of the country. It seems to be less 

 frequent now than formerly. In warm countries it be- 

 comes malignant ; thus, in India it is manifested by high 

 fever, confluence of the vesicae, and the mucous mem- 

 branes in general becoming involved in the diseased action. 

 Thus, there is a discharge from the nostrils, profuse saliva- 

 tion, diarrhoea, and abdominal pains. Young animals and 

 weakly subjects even succumb to the disorder. 



Treatment. — Prevent retention of milk, such as is apt 

 to occur by scabbing over of the extremity of the teat. 

 Draw off the milk regularly with the syphon. Occasionally 

 mammitis results from extension of inflammation along the 

 mucous membrane of the gland. This will require the 



