894 Contagious Pustular luflammatiou of the Skin. 



Cultivation. The bacilli grow best at body temperature on solidi- 

 fied cattle or horse blood serum ; they assume the form of small round 

 colonies which are at first pure white and later on yellowish gray. 



Pathogenicity. The introduction of a few drops of the 

 culture diluted with water, by friction, into the healthy or super- 

 ficially scarified skin of a horse produces typical pustules. In 

 calves, dogs and sheep the effect is similar but milder. In the 

 rabbit, on the contrary, a severe inflanmiation of the subcu- 

 taneous connective tissue develops which may lead to death, 

 while guinea pigs die of septicemia two days after rubbing in 

 of even a moderate amount of the culture. 



Natural infection takes place through parts of the harness 

 as well as through cleaning utensils. The favorite localization 

 of the disease is on the saddle region and on the chest wall, in 

 all probability owing to the fact that these parts are pressed on 

 by the saddle or girths ; the hyperemia produced by the pressure, 

 and possibly also superficial losses in the continuity of the epi- 

 dermis aause the infection to ])e established more easily in these 

 places, but the eruption occurs also, less often, in other places, 

 particularly on the extremities. 



Symptoms. Two to three days after artificial, somewhat 

 later (according to Sehindelka 6 to 8, and even 14 days, at times 

 as early as 24 hours [Liihrs]) after natural infection the 

 skin swells at one or several round or oval places from a one 

 cent to a twenty-five-cent piece in size, becomes warmer and 

 more sensitive, its surface moist, while the hair appears ruffled. 

 Soon hemp-seed to lentil-sized vesicles with thin walls develop 

 in variable number on the swollen parts of the skin ; their con- 

 tents, which are at first generally turbid, in a short time become 

 purulent. The thin wall of the vesicle or pustule generally 

 bursts after one to two days, whereupon its contents dry up and 

 form thick, honey-yellow, gluey, tenacious, flat or centrally de- 

 pressed crusts, under which grayish white or grayish green pus 

 collects. Meanwhile a fresh layer of epidermis forms under the 

 crusts, the crusts loosen and fall off, together with the hair, 

 after about a week, and in their places round, hairless, colorless, 

 non-scaling patches remain, which later are covered by new 

 hair. During the whole time the skin between the inflamed sur- 

 faces remains healthy. 



The development of the exanthema occurs without itching, 

 without fever or any signs of ill health, only the parotid glands 

 and the thyroids swell acutely in isolated cases, but this s>anp- 

 tom disappears when the vesicles dry up. In mild cases the 

 affection passes off in 3 to 4 weeks, while eruptions may arise in 

 the neighborhood from the broken up morbid products of the 

 affection. 



After a very severe infection or by keeping animals at 



