THE MORPHOLOGICAL APPROACH 89 



and Schaefer (1957). Following inoculation of embryonic chicken cells with 

 sufficient virus to infect 90 % of the cells, the appearance of this antigen and 

 the hemagglutinin antigen was followed. At 3 hours the bound antigen was 

 jDresent in the nucleus, whereas the hemagglutinin was found throughout the 

 cell, with special concentration in the paranuclear area. Hemagglutinin 

 antigen was found in the filaments. 



G. Incomplete Virus 



Morphological study of "incomplete" virus had, until the last year, been 

 limited to observation in purified preparations (Werner and Schlesinger, 

 1954; Bang and Isaacs, 1957). The interaction between Newcastle disease 

 virus and Ehrlich ascites tumors cells is in some ways comparable to the 

 incomplete virus formation. Prince and Ginsberg (1957) showed that fluores- 

 cent staining detected the development of intracellular antigen, even when 

 there was neither a rise of infectious titer, nor any demonstrable hemag- 

 glut mating or complement-fixing antigen. Since the intracellular antigen 

 appeared in scattered cells even when the ratio of infecting particles to cells 

 was less than one, it was assumed that the antigen increased within the cells. 

 However, the antigen appeared only when the cell virus system was inocu- 

 lated intraperitoneally in mice. A subsequent electron microscope study by 

 Adams and Prince (1957) of this same cell system brings out the develop- 

 ment of masses (apparently mostly paranuclear) in which a collection of 

 small granules of about 3 to 14 m/x in diameter is surrounded by multiple 

 lamella. The external portion of these lamellae are continuous with the endo- 

 plasmic reticulum. As suggested by the authors, this hypertrophied lamellar 

 system may represent the fluorescent staining antigen. Further studies on 

 other virus systems will probably reveal more lesions of this kind, but an 

 interpretation of the events is not justifiable as yet. 



IX. Adenoviruses 



A. Cytochemistry 



This newly discovered group of viruses, first uncovered because of their 

 effect on human tissue cultures (Rowe et al., 1953; Hilleman and Werner, 

 1954), has been studied almost exclusively in tissue culture as far as their cell 

 lesions are concerned. Although the first analysis of their remarkable intra- 

 nuclear lesions was with the electron microscope (Lagermolm et al., 1957; 

 Harford et al., 1956; Morgan et al., 1956b), we will review their effect as seen 

 in stained, unsectioned material first. In a study of the sequential changes 

 which occurred in HeLa cells infected with types 1 to 4, Boyer et al. (1957) 

 found that types 1 and 2 could be differentiated from 3 and 4. In the first 



