HOG-CHOLERA. 45 



affected, the disease was not eradicated, nor did its fatality seem to 

 be lessened. The extension of the disease from one herd to another 

 was greatly diminished ; but in infected herds where the malady 

 was already prevailing when cold weather set in, there appeared 

 but little difference in the rapidity of the transmission of the dis- 

 ease from one animal to another in the same lot." 



Dr. Law confirms this statement, for his experiments proved 

 that " the severe frosts of winter do not destroy the germs of the 

 malady, but simply retard their conveyance from one herd to an- 

 other." 



In another place Dr. Law says : " I have demonstrated that the 

 freezing of the virulent matter does not destroy its activity, and 

 that the virus loses nothing in potency by preservation for one or 

 two months closely packed in dry bran. The same may be inferred 

 of all other situations when it is closely packed, and where the air 

 has imperfect access. These last two points are of immense im- 

 portance as bearing upon the question of the preservation of the 

 poison in infected pens and yards, alike in winter and in summer, 

 to say nothing of its possible conveyance by means of fodder or 



other vehicles." 



Incubation. 



According to the average drawn from a large number of obser- 

 vations, the period of incubation varies from five to fifteen days. 



Intka-vital Phenomena. 



One of the very earliest symptoms is a marked rise in the tem- 

 perature of the hog ; yet the fact is not without some questionable 

 diagnostic value : first, on account of the variations which seem to 

 exist in the normal temperature of different hogs ; and, second, the 

 difficulty which the struggle of the pig throws in the way of the 

 proper application of the thermometer, which may in some cases 

 cause a more or less marked rise in the temperature. Detmers does 

 not consider the thermometer of any great value in the diagnosis 

 or prognosis of this disease. The disease frequently announces it- 

 self by a cold shivering on the part of the afflicted swine, lasting 

 from a few moments to several hours, frequent sneezing, and more 

 or less coug-hins:. 



These anticipatory symptoms are soon followed by a more or less 

 loss of appetite, a rough and somewhat staring condition of the 

 bristles, a drooping of the ears, loss of vivacity, and in some cases 

 by vomiting ; a desire to bury themselves in the bedding and to lie 

 down in dark and quiet cornel's ; a dull and injected condition of 



