VI. THE SHAPE OF VIRUS PARTICLES 79 



believe that the filaments can undergo segmentation into virus par- 

 ticles (72) (73). 



If protoplasm has a structure just as the writer postulated, it will 

 only naturally follow that viruses have such various forms. Although 

 a phage is customarily regarded as having a definite size and shape, 

 a variety of irregular and incomplete forms was shown in the 

 untreated bacterial cultures lysed by a phage, and even filaments were 

 found in a culture obtained at a low temperature (74). Observations 

 made by Chapman (75) in electron micrographs of a certain strain of 

 phage revealed various shapes of phage or phage-like particles, includ- 

 ing not only the familiar type of a body with a single tail, but also 

 dumbbell-shaped particles with or without tails, or various shaped 

 bodies with one or more tails at each end, as well as the filaments or 

 rod-shaped particles. 



Hoyle (76), in his study of chorio-allantoic membrane of chick 

 embryo infected with influenza virus by means of dark-field optical 

 microscopy, suggested that elementary infectious units of influenza 

 may be cellular fragments. On the other hand, Wyckoff (77) showed 

 in electron micrographs of the same materials similarly extruded and 

 detached bits of cytoplasm mainly consisting of filaments which in 

 turn tends to segregate into spheres. These views and observations 

 are of course consistent with the writer's findings and conceptions. 



If host cells are not injured and broken up following virus infec- 

 tion, but can remain in their unchanged, complete forms, then the 

 coagulated elementary bodies, which may be able to act as separate 

 virus particles if freed from the cells, must exist in the protoplasm 

 in a regular arrangement, because the protoplasm consists of elemen- 

 tary bodies so arranged. It has actually been found in electron mic- 

 rographs that virus or virus-like particles are arranged regularly in a 

 crystal pattern in bacterial or some plant cells affected by respective 

 viruses (78). In a similar way Straus (79) showed that virus-like par- 

 ticles in a equally regular arrangement are present in protoplasm of 

 papilloma cells. 



Particles of various shapes are found also in normal cells without 

 concerning any virus infection (80), indicating that protoplasm protein, 

 in general, has the property to change its shape in various ways. 



Wyckoff (81), in his study by electron micrographs on the forma- 

 tion of the particles of influenza virus, has confirmed that there is no 

 essential morphological difference between particles arising from 

 "healthy" cells and virus particles coming from cells infected with 

 influenza. They both resemble bits of cellular cytoplasm rather than 

 extraneous objects growing and multiplying at the expense of the 

 cell. He stated that, if influenza virus particles are fragments of a 



