xiii, b, 3 Boynton: Use of Organ Extracts 155 



tion on account of a slight fault in the technic of administering 

 it. Since the skin of a carabao is thick, it is difficult to use 

 a small injection such as 5 cubic centimeters and be sure one 

 has good penetration of the virus. When working with this 

 type of animal, it is best to give at least 10 cubic centimeters at 

 an injection. If but 5 cubic centimeters of the material is 

 desired, it can be easily diluted to 10 cubic centimeters with 0.85 

 per cent sodium chloride solution without affecting the activity 

 of the virus, and in this way the necessary amount of material 

 is available. 



The animals on which the extract was used were the ordinary 

 type one has to handle in the immunization stations, as they 

 were obtained from localities where rinderpest had been present 

 for a number of years, and many of those brought to the station 

 had passed through the' disease by natural contact. Since at 

 present there is no way of identifying the immunity, all animals 

 are subjected to the same treatment. This accounts for the high 

 percentage of nonreactors obtained in this work. From the 

 results obtained by the use of extracts, Doctor Youngberg states 

 that it has the same efficiency as the most potent virulent blood. 

 With a strong strain of virulent blood he usually obtains about 

 50 per cent reactors on the first injection. With the extract, 

 slightly over 50 per cent of reactions were obtained, or in other 

 words it picked out all the susceptible animals but one. The 

 possible reason for this one not becoming infected from the 

 extract has been mentioned. 



In using the extract for hyperimmunization, we have obtained 

 some very satisfactory results, but there have been a few in- 

 stances where the massive injection of this highly virulent mate- 

 rial has resulted in the death of the animal. The possible causes 

 for this will be discussed in connection with these animals. 



The first hyperimmunization work with tissue extracts was 

 accomplished by Doctor Patdu, upon Chinese cattle. These an- 

 imals were imported to the Philippines to be used as work 

 animals. Before they could be shipped to the provinces, they 

 had to be immunized against rinderpest, which was accomplished 

 at the quarantine station. 



Fourteen of these Chinese cattle that had passed through an 

 attack of rinderpest during the immunization process were hyper- 

 immunized with fixed tissue extract obtained from three different 

 animals. These extracts were prepared in 0.5 per cent phenol 

 and were 5 days old. Thirteen of the animals received 1,500 

 cubic centimeters each of this extract, and one received 1,200 

 cubic centimeters. None of these animals developed any serious 



