274 IV. THE PRINCIPLES OF LIFE PHENOMENA 



season as described in Chapter III in Part III. This may be elucidated 

 by considering that the pattern of measles develops in some seasons 

 while disappears in other seasons. It seems probable that immature 

 pattern of a virus present in some organisms cannot develop to a full 

 form unless proper conditions are provided. Phage can be detected in 

 chicken feces in warm seasons only, especially in summer, as stated 

 already, a fact which suggests that the immature pattern of phage in 

 chicken cells develops its complete pattern in summer. Even the virus 

 pattern present in lysogenic bacteria can develop into complete form 

 only when adequate conditions are provided (82). 



In view of these facts it seems difficult to distinguish a newly 

 generated virus from a virus inherited from parent. The discrimi- 

 nation of the two forms, however, may not be impossible, as in general 

 in contrast to fixed, advanced viruses, the structure of newly generated 

 ones must be weak and accordingly they are unable to give rise to a 

 long-lasting immunity, that is, they cannot exist for long periods of 

 time in host cells, not to speak of the transmission to progeny. Fur- 

 thermore, newly generated viruses may be liable to undergo variations 

 because of their weak structure, so that their immunological specifi- 

 city is inconstant, whereas the pattern of fixed viruses is generally 

 invariable, being transmissible unchanged in hosts from generation to 

 generation. 



Herpes simplex virus appears to be generated by various factors, 

 especially by febrile diseases ; the disease is said to occur also after 

 artificial pyrotherapy. It seems reasonable, however, to regard this 

 virus as a typical fixed virus. Burnet (83) has claimed that the most 

 individuals acquire herpes virus in childhood, as in the case of meas- 

 les, and carry it for the rest of their lives. After the first infection 

 wnth this virus, individuals develop neutralizing antibodies in their 

 serum which remain present for many years. Persons who have been 

 infected with this virus can thus be detected by serum neutralization 

 test, indicating the constancy of its antigenical specificity as well as 

 the long duration of its existence in the host. The causative agent, 

 such as fever, may therefore aid only the virus pattern inherited 

 from the parent to develop into its complete structure. 



