108 Missouri Agricultural Report. 



uary 28th, through a misunderstanding on the part of the assistant, 

 this entire lot, including the two that were fed the viscera, were 

 inoculated two days later with 1 c. c. each of infected blood, from 

 a pig that had died from a natural attack of cholera,* and in which 

 the typical lesions of the disease were found ; as ulceration of the 

 bowels, enlarged spleen, swollen and haemorrhagic lymph glands, 

 and haemorrhagic spots on the surface of the kidneys. Nothwith- 

 standing this very severe exposure not one of these vaccinated pigs 

 has shown the slightest symptoms of illness of any kind. 



Lot 4 (pen 1). In this lot were nine pigs, varying in weight 

 from 35 to 70 pounds. Six of the smaller ones averaged about 50 

 pounds; the three larger ones were gilts, one of which was preg- 

 nant. 



This lot of hogs was used in an experiment to test the "im- 

 munizing value" of the blood serum of a hog that had become im- 

 mune to cholera through a natural attack of the disease; and had 

 been fed from time to time over a period of two years with large 

 quantities of viscera (spleen, liver, intestines and kidneys), from 

 hogs affected with cholera (from natural attacks), with the view 

 of increasing the acquired immunity. It was to be presumed that 

 an animal so treated would acquire some degree of "hyperimmun- 

 ity" and would produce a more potent serum than the ordinary 

 "recovered" immune. 



October 22 six of the smaller hogs of lot 4 were injected with 

 20 c. c. of freshly drawn serum, from the "viscera-fed immune" 

 mentioned, at the same time these six hogs were injected with 

 virulent hog cholera blood; three with fresh hog cholera blood 

 from the same source as that used on lots 1 and 2. The other three 

 were injected with preserved hog cholera blood from the same 

 source as that used on lot 3. The infectiousness of this blood was 

 shown by its fatal effects on two pigs that were injected with this 

 alone, and isolated from any other source of infection. 



November U, thirteen days after the vaccination of the six pigs 

 of the above lot, three of the vaccinated pigs seemed to be sick, 

 and seven days later (November 11), one of the sick vaccinated 

 pigs died; this one had been injected with 20 c. c. of serum from 

 the "viscera-fed" immune hog, and simultaneously with 2 c. c. of 

 fresh infected blood. The autopsy showed an acute haemorrhagic 

 case of hog 'cholera. The other two sick pigs recovered ; one had 

 been injected with 1 c. c. of the fresh virus, and the other with 1 

 c. c. of the preserved virus, The remaining three vaccinated pigs 



'Gentry Olark herd. 



