X. THE SUMMARY OF PART II 121 



viruses are actually believed to be so small particles as their diameter 

 are of the order of 0.03/^ or less. 



This is probably true also for the virus particles from which 

 lipids are not eliminated. Thus, if coagulated fragments yielded by 

 the split of elementary body retained the virus activity, the virus in 

 question would be said to be very small particles. On the other 

 hand, if every several elementary bodies were coagulated into a 

 larger body on the combination with one another, the virus would 

 reveal itself as a large particle, and if a number of elememtary bodies 

 associated end-to-end and subsequently coagulated, thread-like parti- 

 cles would be produced. 



Protoplasm proteins may be able to accomplish a reversible con- 

 traction not only in the protoplasm but also outside the cell, so that 

 certain viruses may be globular under some environments while filaments 

 under others. If some proteins in an elementary body were left in 

 the stretched state while most molecules were coagulated or folded, 

 then the so-called tailed-virus would appear. 



The origin of various shapes and sizes of virus particles can thus 

 be explained by the above concept concerning the protoplasm structure. 

 At the same time it should be expected from the same concept that 

 there may neither be shape nor size essential to virus particles. Vari- 

 ous virus-like particles can be obtained from cells having no concern 

 with viruses. 



Nevertheless, it seems to be an established fact that particles 

 which fail to be found in the normal cells can frequently be demon- 

 strated in virus-infected cells by electron micrographs. Considerable 

 changes may take place in the metabolic activity of cells when they 

 are affected by viruses, resulting in the production of a different pattern 

 in their chemical composition, especially in both amount and kind of 

 nucleic acids. On account of such a change particles may become 

 stable enough not to be disintegrated under the electron beam so 

 that they are photographed fairly by the electron microscope. Thus 

 particles appearing not present in the normal protoplasm will be 

 raised on the infection with certain viruses. 



According to our investigation under the microscope by dark-field 

 illumination, red blood corpuscles, like other cells, are disintegrated ■ 

 into virus-like particles on the application of adequate injurious 

 effects. But such particles cannot be photographed by the electron mic- 

 roscope unless Ringer's solution is used, and even with Ringer's solu- 

 tion the particles are sometimes disintegrated into much smaller ones 

 and photographed as such ; the use of saline instead of Ringer's solution 

 may result in the failure of catching any particles in the electron 

 micographs. Thus certain particles which do exist actually cannot be 



