xiii, b, s Boynton: Virulence of Body Organs in Rinderpest 139 



May 5, this animal's temperature was normal, and it was well 

 on the road to recovery. 



June 1, carabao 92 received 50 cubic centimeters of virulent 

 blood, which had no ill effect upon it, proving that the animal 

 was immune to rinderpest. In addition, this animal was con- 

 stantly exposed to animals in various stages of the disease. 



From this result it appears that the virus in this case had 

 become slightly attenuated by the extraction. 



EXPERIMENT 15 



Phenol (0.5 per cent) extract of liver, spleen, and lymph 

 glands, 29 days old. 



Carabao 10 %. — Known history prior to the experiment: Native 

 Jolo carabao, 7 years and 5 months old, received at the labora- 

 tory and placed in quarantine March 3, 1917. This animal was 

 kept under observation for seventy-one days before it was used ; 

 it did not present a high temperature or develop any symptoms 

 of sickness during this period. 



May 14, 1917, carabao 104 was injected subcutaneously with 

 200 cubic centimeters of a 29-day-old 0.5 per cent phenol extract 

 of the liver, spleen, and lymph glands from carabao 240 (P. C. 

 W.), which was bled to death on the third day of temperature 

 for virulent blood, to be used in immunization work. 

 The extract was prepared as follows : 



Liver, 300 grams; 0.5 per cent phenol, 600 cubic centimeters. 

 Spleen, 300 grams; 0.5 per cent phenol, 600 cubic centimeters. 

 Lymph glands, 150 grams; 0.5 per cent phenol, 300 cubic centimeters. 



This was placed in the refrigerator for three days ; it was then 

 filtered through gauze, and the filtrate was returned to the 

 refrigerator. 



When the extract was injected, the liver had a slight butyric 

 acid odor. The other extracts were sweet, presenting no evi- 

 dence of putrefaction. 



May 24, which was ten days after the injection, carabao 104 

 presented a forenoon temperature of 39° C. ; afternoon, 39° C. 



May 25, forenoon temperature, 39.4° C. ; afternoon, 41.3° C. 



May 26, diarrhoea, eating little; forenoon temperature, 39.9° 

 C; afternoon, 38.7° C. 



May 27, the animal was eating well and its temperature re- 

 gistered normal. This animal rapidly recovered from the slight 

 attack and to date has not presented any signs of rinderpest, 

 although constantly exposed to the disease. 



From the results of this experiment it appears that the virus 



