308 THE DISEASES AND DISORDERS OF THE OX. 



the pustules of small-pox. Like them, they begin as papules 

 which in a few days are converted into vesicles containing 

 a viscid yellow fluid. These vesicles gradually increase in 

 size, until in about eight and a half days they are about five- 

 eighths of an inch in diameter. In the middle they have a 

 light-blue tint; but towards the margin they are reddish-blue 

 or yellow in colour. Their contents then become purulent. 

 The centre is usually depressed, and a crust begins to form 

 there, and gradually extends to the periphery. The border is 

 hard, swollen, and painful, and a red areola forms, together 

 with much thickening under the skin. 



About the fourteenth day a scab, which is thick, dark, 

 adherent, and shining, is formed, and about the fifteenth day it 

 becomes detached, leaving a depressed scar, which is at first bluish- 

 red, and gradually turns pale, and persists for a long time. 

 The febrile symptoms are very slight, and generally unimportant, 

 and the infection is not a dangerous one. A partial loss of 

 appetite, an abstention from chewing the cud, trifling constipation, 

 diminution and deterioration of the milk are to be observed. 

 The udder is swollen, especially near the teats, and milking causes 

 pain. There may be more than one eruption of pustules. 



Cow-pox generally lasts about seventeen and a half days, but 

 may be protracted for about five weeks. The vaccine matter for 

 vaccination purposes is generally collected at about the fifth 

 day after the first appearance of the pustule. The course 

 of the malady is usually favourable, at least in western countries. 

 The milk should not be used for human food, so long as the cow 

 is suffering. The disease may be conveyed by contact from cow 

 to cow, by the hands of milkers both from one cow to another, 

 and also directly from small-pox pustules of the attendants, or 

 by injection of the virus into the blood-vessels, or by ingestion 

 of it through the mouth. It will be clearly seen that the 

 animals which are aff'ected should be milked last, in order that 

 the virus may not be taken from cow to cow. Perfect cleanli- 

 ness in all points, care in milking, and suitable treatment of any 

 secondary local results must be thoroughly attended to. 



Messrs. Ceely and Badcock inoculated cows with small-pox 

 lymph, and the result was that at the seat of inoculation pustules 

 exactly like those of cow-pox were produced. Moreover, with 

 the contents of these they imparted cow-pox to healthy cattle. 



