METCALF 



ordinary temperatures, but one can raise the body temperature 

 sufficiently so that even this multiplication is choked off. 



NUNGESTER: This pancreas thing intrigues me very much. 



WALKER: It intrigues me, too, because there are other vi- 

 ruses that seem to multiply well in the pancreas. 



NUNGESTER: But by and large, the pancreas is not suscep- 

 tible to bacterial infection, at least as far as I know. 



WALKER: But I think it is susceptible to a number of viruses. 



REINHARD: I might offer the information of some recent gastro- 

 enterological research which indicates that the pancreas has 

 different proclivity for amino acid uptake. Certain kinds of amino 

 acids are readily absorbed by the pancreas, and this might be 

 one of the differences causing increased tissue susceptibility. 



WALKER: So far, we have had great difficulty in trying to 

 get it to persist or multiply in culture. 



METCALF: Dr. Walker, I think you have a very interesting 

 theory. In view of your results as well as the work of Dubos and 

 Wenner,^ I wonder if you are forced to describe a polydisperse 

 virus population with respect to genetic variance. Are you se- 

 lecting one member of a polydispersed population at a given 

 temperature? 



WALKER: I am not any more worried with that than with any 

 other explanation of multiplication at any temperature. I think 

 temperature is going to be a selective force on virus popula- 

 tions, and I think that, as Lwoff has shown, it is possible to 

 isolate strains that are capable of multiplying at higher tem- 

 peratures. This is part of the basis for his contention that tem- 

 perature is related to virulence. Is this pertinent to your question? 



1 Dubes, G. R., and H. A. Wenner. Virology 4: 275-296. 



364 



