VIRUS GENETICS, MULTIPLICATION, AND PHYSICS 199 



ultiiiiiitely highly vuhicrable i)art of the virus is this, and iiiik\ss 

 it is damaged the virus will survive, although with impaired 

 properties. The eight units are thought of as eight genetic com- 

 ponents. They can mutate and, if such forms are stable, recom- 

 bination could occur. The outer layer of protein, which does not 

 enter the bacterium, is shown as an intact sheath. The protein 

 units which control the latent period are shown as white blocks. 

 The tail of the virus (the most convenient part to draw) is shown 

 in more detail and is broken into a mosaic of antigenic units 

 carrying a pattern of charge distribution which is specifically 

 related to the charge distribution on the bacterium. Undoubtedly 

 the virus is hydrated inside, and this is shown. The outer hy- 

 dration has been omitted, as its thickness is a pure guess. 



Finally, on very slender evidence, we show Newcastle disease 

 virus. This is guessed at as spherical in the resting state, but is 

 probably formed by coiling up an elongated structure which is 

 the form it takes in the host. The lipid fraction is shown on the 

 outside, with islands of protein penetrating through to form the 

 hemagglutinins, which are of about the size indicated by deute- 

 ron bombardment. The virus is certainly very much hydrated, 

 and this has been indicated as partly in the center and jjartly 

 extending between the nucleoprotein units. The virus is a poor 

 antigen, probably due to the lipid layer. It is very radiation sen- 

 sitive, almost as much so as TMV, which argues for a rather 

 simple internal structure. 



We feel like insisting that these pictures be treated as specula- 

 tive and tentative. However, in the author's experience, they 

 have excited much interest and, after all, presumably viruses do 

 have a functional internal structure — so why not say so. It is 

 only in the event that these pictures should be treated as author- 

 itative descriptions of the viruses that harm could be done. Prob- 

 ably in five years such authority can be justified — but not at the 

 present time. 



The Energy Turnover in the Host 



One basic process which must be concerned with virus multi- 

 plication is the energy turnover, or metabolism, of the host. This 



