CHAPTER IV 



SIZE AND MORPHOLOGY OF 

 BACTERIOPHAGES 



The presence of phage particles inside the infected bacterial 

 cell and the release of these particles on bursting of the cell were 

 seen in the dark field microscope by d'Herelle (1926) and 

 photographed by Merling-Eisenberg (1938). The agglutination 

 of phage particles by antiphage serum was photographed in the 

 ultraviolet microscope by Barnard (Burnet, 1933c). Although 

 there is no difficulty in seeing light scattered by the larger phages 

 under these conditions, they are not resolved by light micro- 

 scopes. Consequently our knowledge of the morphology of the 

 particles begins with their examination under the electron 

 microscope. 



1. Electron Microscopy of Bacteriophage Particles 



The electron microscope was first applied to the study of 

 phages by Ruska (1940) and Pfankuch and Kausche (1940). It 

 was soon clear that the particles are striking and characteristic in 

 shape (Ruska, 1943; Luria, Delbriick, and Anderson, 1943). 

 Most of the phages examined resemble tadpoles, with long tails 

 attached to spherical, cylindrical, or polyhedral heads. Some 

 phages at first thought to be tailless spheres revealed on closer 

 examination polyhedral shapes and a rudimentary tail (Wil- 

 liams and Fraser, 1953). In numerous instances the tail proves 

 to be a specialized organ for attachment to bacteria ; very likely 

 all phages possess such an organ (T. F. Anderson, 1953). Mi- 

 crographs of several phages are shown in Figures 1, 2, and 3 

 and the frontispiece of this book. 



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