274 Hog- Cholera. 



acute cases tlie mucous membranes of the gastro-intestinal 

 tracts, as well as of the lungs, are simultaneously affected in 

 the above-described manner, while in chronic cases one or the 

 other form is often exclusively present. 



Symptoms. The time of incubation of hog cholera in arti- 

 ficial infections, carried out as closely to the natural mode of 

 infections as possible (cohabiting healthy animals with affected 

 hogs, or in infected premises, Preisz, Hutyra), is at least 4 

 days, usually however 13 to 18 days. After a subcutaneous 

 injection of virulent blood the first symptoms also appear at the 

 earliest on the fifth day, more frequently however in 8 to 10 

 davs, and in some cases only after from 2 to 3 weeks (Uhlen- 

 huth). 



1. Pure Hog Cholera (septicemic form). Excepting the 

 very rare peracute cases which develop almost exclusively at 

 the beginning of an outbreak and terminate in from 2 to 3 days 

 with manifestations of an acute hemorrhagic septicemia, the 

 clinical development of the acute cases is usually somewhat 

 slow. One of the first indications of the presence of the disease 

 is impairment of the appetite. Tlie animals take their food less 

 eagerly, they separate, apparently quickly satisfied, from the 

 other animals of the herd, stand at one side, alone, or crawl into 

 some secluded corner of the stable or yard. Later they appear 

 only hesitatingly or not at all for their feed. If urged to leave 

 their place they show great reluctance to move, and do so slowly 

 and feebly. They soon stop, and remain for long periods in 

 one place with back arched, and with head depressed. 



One of the first symptoms and one almost invariably present 

 is an acute conjunctivitis, with the production of a mucous or 

 muco-purulent secretion. Vomiting is frequently observed on 

 the first or second day, the vomited material containing mucus 

 and being stained yellow by bile. There is at first constipation, 

 but diarrhea sets in after a short time. The feces are thin and 

 sometimes bloody. In this stage the patients become more 

 or less weakened, and if the disease does not turn toward im- 

 provement, or if it does not become chronic, death ensues in 

 from 4 to 7 days, with septic manifestations. 



2. Intestinal Form. This develops like the first form, but 

 is less acute. The more intense affection is indicated by a dis- 

 tinctly yellowish or greenish coloration, and by the very fetid 

 odor of the feces. At the same time inflammatory or diphtheritic 

 changes appear on the buccal mucous membrane. The borders, 

 the dorsum and the base of the tongue, the cheeks and the 

 pharynx become covered with a dirty gray or yellow, loose^ de- 

 posit of exudate, the tonsils are greatly swollen, or ulcerations 

 covered by a mushy mass develop upon them. These changes 

 may be observed by examining the buccal cavity. There is also 



