3i8 MICRO-ORGANISMS AND DISEASE [chap. 



Some of the vesicles contained clear lymph, others were 

 pustular, i.e. purulent. 



On the seventh day new papules and vesicles were 

 found ; those of the previous day had already become 

 changed into dark brown crusts. On the eighth day a new 

 crop of vesicles could be noticed on this cow's udder, and 

 on that day for the first time about half a dozen were also 

 seen on the udder of the second cow. Some were vesicular, 

 others pustular, and still others covered with brown-black 

 crusts ; the vesicles and pustules were round and prominent, 

 with a narrow margin of injected skin, the crusted places 

 irregular. The whole thickness of the skin and subcuta- 

 neous tissue felt hard, nodular. For two or three days (ninth 

 to twelfth day) did this go on in the first cow ; that is, new 

 vesicles appeared : those that were vesicles with clear lymph 

 one day were pustular the next, and crusted the following 

 day. The crusts did not remain long ; after two or three 

 days they became loose, and left a dry healing sore behind, 

 but when recent, on removal, showed a bleeding sore of the 

 corium underneath. 



We have, then, here a new eruptive disease on the teats 

 and udder of the cow : a disease marked by papule, vesicle, 

 pustule, sore and crust, but of a very rapid progress, since 

 the crusts fell off and the sore healed in less than seven to 

 nine days since its first appearance, the skin being at the 

 same time much indurated. This eruptive disease on the 

 udder, be it well observed, was produced by inoculating 

 the animals subcutaneously in the region of the left shoulder 

 with a culture of the bacillus diphtheriae. 



As stated above, in both animals on the second and third 

 days there was a painful soft tumour to be felt at the seat 

 of inoculation. From day to day the tumour became 

 larger ; about the end of the week it was as large as a man's 

 fist ; after this time it gradually became firm ; but about the 



