SIZE, SHAPE, AND HYDRATION OF VIRUSES 



19 



Fig. 2.1. Electron micrugraplis of viruses: (a) is T-1 bacteriophage, (b) is 

 southern bean mosaic virus, and (c) is tobacco mosaic virus. These were 

 taken by Dr. Fluke at Brookhaven National Laboratory. 



and observed, the nature of the cross section of the virus is 

 seen to be hexagonal with a side of length 87 A. One such electron 

 micrograph is shown in Fig. '2. "2, There is a consideral)le future 

 for this combination of physical disturbance and subsequent 

 electron microscojjy. 



One feature of electron microscopy which is of great impor- 

 tance is the observation of the virus in association with the 

 host organism. This is possible for bacterial viruses and also, 

 by the technique of embedding a tissue section in methacrylate 

 and then cutting thin sections, can be applied to j^lants and 

 animal viruses. The section technique was described by Neuman, 

 Borysko, and Swerdlow (1949), and if metal shadowing to 

 prevent the development of charge on the slice is used, excellent 

 micrographs are obtained (Miihlethaler, 1952), An example of 



