Fig. 5. Tobacio mosaic virus 

 on a younu; tobacco plant. 



Fio. (5. Crystal of tobacco mosaic 

 virus. i)hotOiiraphed at rii^lit angles 

 t(j the hexagonal j)Iane in polarized 

 light, and showing the alternating 

 (lark and light bands. Tlie distance 

 between dark bands is twice the 

 length of the virus rods (Magnifi- 

 cation: X 2,100). Photograph by 

 Dr. M. F. Wilkius. 



Fig. 7. Liquid crystalline 

 ("bottom layer"") tobacco 

 mosaic virus oriented ])y 

 flowing on aglass slide. Photo- 

 graphed in polarized liuht. 



