﻿IX, B, 1 Ward et al.: Transmission of Rinderpest 61 



Table IX. — Exposure of susceptible animals in infected corral. 



Animal No. 



Interval 

 between 

 removal of 

 sick and 

 exposure 



of sus- 

 ceptible 



animal. 



Time of 

 exposure 

 in corral. 



Result. 



Susceptibility 

 test later. 



3073 



Hours. 

 0.5 

 17.5 



24.0 

 24.0 



Days. 



7.0 

 6.0 

 • 6.5 

 6.0 

 6.0 



Positive -_.. 



L...do 



Negative . . . 

 do 



Susceptible 

 Do. 



3069 



3174 



3175 





" Hours. 



The results of this experiment tend to confirm those previously 

 obtained. They lend color to the belief that in former exper- 

 iments in this corral the infection had really perished and that 

 the failure of animals to become infected was not due to mere 

 accidental avoidance of infected spots. 



The series of experiments demonstrated the necessity of at- 

 tacking the problem from a different angle, as described in the 

 following experiments. 



PERIOD OF INFECTIVENESS DURING ATTACK 



Experiment 11. — This experiment was desigTied to furnish 

 information regarding the relation between the period of infec- 

 tiveness and the stage of the disease in cattle. It was not so 

 arranged as to permit of discrimination between infection ob- 

 tained directly from the sick animal on a given day and that 

 which might be obtained from virus several days old that had 

 resisted natural disinfecting agencies. This latter possibility 

 seemed improbable in view of the results obtained in the fore- 

 going experiments. 



Two bulls, 3001 and 3060, were injected with virulent rinder- 

 pest blood on April 14, 1911. These were placed in a small 

 corral, 7.2 by 5.3 meters, and consequently it was possible to 

 determine only facts concerning the joint infectiveness of the 

 two. The corral was well shaded and usually in a muddy con- 

 dition. Opportunity for the transmission of infection by close 

 crowding and the use of the same drinking-water bucket and 

 feeding trough were encouraged. The animals habitually placed 

 their feet in the feed box. A photograph of this corral is shown 

 in Plate II. The other susceptible cattle were placed in imme- 

 diate contact with them in turn for a period of twenty-four 



