﻿IX, B. 3 Boynton: Cultivation of Rinderpest Virus 267 



that if there was any toxin formed in the medium after a forty- 

 eight-hour incubation period it was so small in amount as to 

 have no immediate ill effect upon the animal in question. From 

 the incubation period, together with the symptoms and lesions 

 presented upon autopsy, it is evident that the virus was not 

 killed and that it had lost practically none of its virulence. 



In addition to the experiments recorded in this article, three 

 animals were injected in a similar manner with virulent rinder- 

 pest blood which had been incubated for three days. In each 

 case, no ill effect followed the injection. It was concluded that 

 in none of these cases was a harmful amount of rinderpest 

 toxin produced, nor was there evidence that the rinderpest virus 

 survived in the medium. < 



CONCLUSIONS 



1. In the case of the two animals in experiments 3 and 5, 

 that died in less time than the incubation period of rinderpest, 

 after injection of the Martin's broth culture, the autopsy find- 

 ings of the tissues indicated death from a bacterial infection 

 and not from rinderpest. All evidence points to the conclusion 

 that the Martin's broth employed in these two cases was con- 

 taminated by bacteria prior to injection in the animals. The 

 results are attributed to poor aseptic technique, and greater 

 care in the subsequent inoculations, where no such toxaemias 

 were induced in the injected animals, support the conclusion. 



The symptoms, lesions, and other circumstances stated by 

 Baldrey resemble the results obtained in the two animals in 

 question, and there is justification for belief that his results 

 were due to the same cause. 



2. In all the other animals injected with mixtures of blood 

 and culture medium after incubation, no immediate ill effect 

 followed, in either susceptible or immune animals. 



3. With the exception of the animals noted in experiments 

 3 and 5, all those injected with the so-called twenty-four- and 

 forty-eight-hour cultures of rinderpest in neutral or alkaline 

 Martin's broth contracted rinderpest after the usual incubation 

 period and died. These observations do not support Baldrey's 

 belief that there occurs a rapid formation of rinderpest toxin 

 in the broth during the twenty-four hours with resulting death 

 of the virus. The experiments have included tests of Martin's 

 broth after incubation as long as seventy-two hours. 



Rinderpest virus does die in Martin's broth culture after 



