316 INFECTIVE DISEASES. 



weaning. This animal was considered in good health, but it looked 

 out of condition. Heat and tenderness of the teats and udder were 

 the first noticed signs. The other two were affected in about ten 

 days. In December 1838, in a large dairy, a milch cow sHpped her 

 calf, had heat and induration of the udder and teats, with cow-pox 

 eruption, and subsequently leucorrhoea and greatly impaired health ; 

 the whole dairy, consisting of forty cows, became subsequently 

 affected, and also some of the milkers. In another dairy, at the 

 .same time, it first appeared in a heifer soon after weaning, and in 

 about ten or twelve days extended to five other heifers and one cow, 

 milked in the same shed, affecting the milkers. And in another 

 dairy thirty cows were severely affected, and also one of the milkers. 

 It appeared to originate in a cow two months after calving. The 

 only symptoms noticed were that the udder and teats were tumid, 

 tender, and hot just before the disease appeared. 



Condition of Animals casually affected. — In some animals, it was 

 less severe than in others, depending on the state and condition of 

 the skin of the parts affected, and the constitution and habit of the 

 animal. It was sometimes observed to diminish the secretion of 

 milk, and in most cases it commonly did actually affect the amount 

 artificially obtained ; with this exception, and the temporary trouble, 

 and accidents to the milk and the milkers, little else was observed ; 

 the animal continued to feed and graze apparently as well as before. 

 The topical effects varied ver}' much in different individuals ; the 

 mildness or severity being greatly influenced by temperament and 

 condition of the animal, and especially by the state of the teats and 

 udder, and the texture and vasculaiity of the skin of the parts 

 affected. Where the udder was short, compact, and hairy, and the 

 skin of the teats thick, smooth, tense, and entire, or scarcely at all 

 chapped, cracked, or fissui'ed, the animal often escaped with a mild 

 affection, sometimes with only a single vesicle. But where the 

 udder was voluminous, flabby, pendulous, and naked, the teats 

 long and loose, and the skin corrugated, thin, fissured, rough, and 

 unequal, then the animal scarcely ever escaped a copious eruption. 

 Hence, in general, heifers suffered least, and cows most, from the 

 milkers' manipulations. 



Progress of the Disease. — Cow-pox once arising or introduced, and 

 the necessary precavitions not being adopted in time, appeared in ten 

 or twelve days on many more cows in succession, so that among 

 twenty-five cows perhaps by the third week nearly all would be 

 affected ; but five or six weeks or more were required before the 

 teats were perfectly free from the disease. 



