100 II. FUNDAMENTAL STRUCTURE OF PROTOPLASM 



stable, being involved in the combining force and able to develop the 

 force even when the virus is in a folded, coagulated state, while the 

 other is unstable, concerned in the repulsive force and revealed only 

 when the particle unfolds. The virus action may be determined mainly 

 by the latter structure against which the replica is to be produced in 

 the host protoplasm, although the former structure also may have a 

 great influence upon the protoplasm in which the complementarily 

 shaped structure is strengthened and specialized by the combination 

 (22). 



According to Anderson (123) phage particles require some amino 

 acids especially tryprophan for the combination with the host cell. 

 These "adsorption cof actors" appear to combine reversibly with the 

 virus particles. This indicates that even for the development of the 

 combining force are needed some factors or conditions. 



A study by Hoyle (124) on the production of the complement-fixing 

 antigens in the various phases of influenza virus infection shows that 

 these antigens, which carry virus specificity without virus activity, in- 

 crease in amount before virus activity appears. Moreover, it has been 

 well acknowledged that at the beginning of the phage infection of bac- 

 teria, large amounts of antigenic substance are formed without being 

 accompanied by the production of infective phage (125.) Presumably 

 the structure formed at the beginning is incomplete, so that at first 

 only the antigenic property may appear, but subsequently, when com- 

 plete structure is accomplished, virus activity may arise. Thus it may 

 be said that the rearrangement of polar groups is established gradually 

 step by step, first only gross structures being formed and then finer ones 

 added leading to the appearance of virus activity. 



It has been shown that there occurs, after the inoculation of a 

 virus, a latent period during which the virus fails to multiply, accord- 

 ing to the virus employed the duration of this period ranging from 6 

 hours with influenza virus to 24 hours with mumps virus (126) (127). 

 After such a latent period, there exists an interval during which the 

 amount of virus in infected tissue increases rapidly. During this latent 

 period only the formation of gross structures are probably being 

 advanced. 



Magnus (12S) has reported an interesting study on the "incomplete 

 virus" : Undiluted allantoic fluid of chick embryo infected by influenza 

 virus was used as inoculum and the amount of both agents concerning 

 haemoagglutination and egg-infection produced after the inoculation 

 were examined, and it was found that an increasing dissociation be- 

 tween the two agents occurred in the course of passages, infectivity 

 decreasing markedly as compared to haemoagglutinin. Magnus con- 

 sidered that this was due to the production of non-infectious haemoag- 



