343 TEXT-BOOK OP BACTERIOLOGY. 



also chickens were refractory. The poison was not absorbed from 

 the alimentary canal even by hogs, if administered by feeding. 



Under natural conditions, this way must be open to the invasion 

 of the bacilli; for, according to the observation of veterinarians, 

 infection occurs almost regularly by the excrements of a diseased 

 animal getting into feed and being eaten by healthy ones. 



The symptoms of erysipelas seem to be essentially the same in 

 all cases, without being affected by a possiblj' varying mode of 

 origin. The outbreak of the disease is generally very sudden. The 

 hogs become faint, show a paralytic weakness of the posterior 

 extremities, refuse food, and their bodily temperature is considera- 

 bly elevated. There appear at the same time, on the skin of the 

 abdomen and chest, irregular red spots which, immediately after 

 artificial infection, are confined to the neighborhood of the point of 

 inoculation, but soon spread and meet in large dark- red areas, not 

 particularly swollen nor painful. Debility increases and death en- 

 sues on the first or second day. 



A very violent infiammatory oedema and a reddening of the point 

 of infection is observed in rabbits after inoculation at the ear. 

 The changes extend rapidly, frequently attack the head and trunk, 

 and occasionally cause the death of the animals. Domestic mice 

 die on the second or third day; before death they present sj'mp- 

 toms of a severe disease and usually squat in a corner of their cage 

 with closed eyelids glued together by a purulent discharge. 



The post-mortem examination will almost always show the 

 same characteristic picture, whether the mode of origin of the hog 

 erysipelas be artificial or natural. The spleen is greatly swollen, 

 hard, and of a thick, brownish-red color; the liver is moderately 

 enlarged; the lungs are peculiarly marbled and spotted. The 

 mucous membrane of the stomach and intestine is reddened and 

 the seat of small hemorrhages; the villi are especially altered, the 

 follicles and mesenteric glands swollen (the latter becoming usually 

 brownish- red) ; the subcutaneous tissue is rather strongly red- 

 dened, bloody, and oedematous. 



The bacilli are met with in all organs, especially in the liver and 

 spleen, more sparsely in the blood; they stain beautifully, even in 

 sections, by Gram's method. They lie in masses in the vessels and 

 occupy preferably the walls of the smaller arteries and capillaries, 

 but they are also found outside of the blood-vessels distributed in 

 the tissue, and usually inclosed in cells. They inhabit (usuallj' in 

 small groups and dense little heaps, rarely singly) the interior of 

 the lymphoid cells, whose body is more or less rapidly destroyed 

 by the foreign intruders. 



