THE MORPHOLOGICAL APPROACH 



65 



and within the nucleus. This will be done for seven general groups of viruses: 

 (1) psittacosis viruses or Miyagawanella; (2) poxviruses; (3) herpesviruses; 

 (4) myxoviruses; (5) adenoviruses; (6) polio viruses; and (7) tumor-producing 

 viruses. The last group, which in our treatment includes the agents respons- 

 ible for mammary tumor in mice, the chicken sarcoma (Rous), and the Lucke 

 frog carcinoma, is the least coherent, but, despite the greater coherence of the 

 others, a number of differences within each group will be readily apparent. 

 For the sake of completeness, some recent work on other viruses will be 

 included. There will, however, be no attempt to review the older literature 

 concerning encephalitis, rabies, and foot-and-mouth disease. 



II. Normal Cell 



Newer concepts of the anatomy of the cell (Porter, 1956; Sjostrand, 1956), 

 as seen with the approximately hundredfold increase in resolution available 

 with the electron microscope, need brief review here (Fig. 1). We will attempt 



mitochondrial 

 network^ 



paranuclear? 

 or juxtanuclear: 



area 



nuclear 

 membrane 



cytoplasmic 

 membra-Tie 



nucleolus 



* mortice! 



ergastoplasm 



Fig. 1. Diagram of generalized epithelial cell showing variety of organized, structures. 

 Mitochondrial network indicated at upper surface is in other cells broken up into more 

 discrete units. Continuity of ergastoplasm with cytoplasmic portion of nuclear mem- 

 brane although not indicated here probably present in many cells. For purposes of repro- 

 duction double mitochondrial membranes are separated by greater distance than 

 actually present. 



to relate them to the much more dynamic picture, as seen in the living cell 

 (Fig. 2) (Lewis and Lewis, 1924; Gey, 1956) but with less resolution. We hope 

 to avoid the controversy concerning the "Golgi apparatus" (Pollister and 

 Pollister, 1957) by referring to the paranuclear area simply as such, and in 



vol. in. — 5 



