﻿IX, B, 1 Ward and Wood: Inoculating Cattle and Carabaos 127 



lots of carabaos as indicated in Table I. All animals immunized 

 subsequently to these received serum drawn in the field. 



The animals while undergoing immunization were confined in 

 large sheds erected by the owners of the carabaos, who likewise 

 fed and cared for the animals during the twenty-five days 

 required for immunizing. 



Each animal to be immunized, while being injected, was con- 

 fined in stocks made of bamboo. It received a hypodermic in- 

 jection of the dose of antirinderpest serum which had been 

 decided upon as sufficient. This standard dose was administered 

 uniformly without reference to the size of the animals. 



In the case of the carabaos belonging to lots 1, 2, 3, and 4 shown 

 in Table I on page 127, it will be noted that gradually increasing 

 doses were employed until there were obtained results thoroughly 

 satisfactory in regard to death rate and severity of reaction. In 

 determining the dose, it was considered advisable to use an 

 amount of serum necessary for the most susceptible animal likely 

 to be encountered, for there exist no means for predicting 

 susceptibility. After the immunization work was under way, 

 the virulent blood was invariably obtained from an animal 

 undergoing immunization at a stage corresponding to the third 

 day of febrile temperature. Thus, there was no expense for 

 susceptible cattle for maintaining a strain of virulent blood, and 

 no trouble of finding natural cases of rinderpest in the vicinity 

 was necessitated. 



In all cases, before virulent blood was employed, it was 

 examined microscopically for the presence of the trypanosomes 

 of surra in fresh and stained preparations. 



One hundred ninety-six of the 429 animals in Table I, 

 which showed no febrile reaction, were reinjected with 10 cubic 

 centimeters of citrated virulent blood. This was done in case 

 that the original virulent blood had been inactive when employed 

 or some accident had prevented its introduction. Up to date, 

 only three distinct reactions from such injection have been 

 observed. 



In the preparation of serum in the field, between 2 and 3 

 liters of blood were drawn from the jugular vein of all recovered 

 animals without reference to whether or not they had reacted 

 to the virulent blood. In a previous (6) paper it has been shown 

 that serum from reactors is somewhat more potent, but with 

 the dose employed this feature was not of sufl^icient value to 

 warrant exempting nonreactors from the bleeding. 



No blood was drawn from very old or very young, nor from 

 pregnant animals. These exceptions reduced the number bled 



