III. THE DEVELOPxMENT OF CANCERS 365 



former pattern. 



Animals and plants, infected with viruses, appear to transmit 

 frequently the viruses to offspring through germ cells. Avian leucosis 

 is looked upon as a kind of malignant tumours and considered to be 

 induced by a virus. It has been established that the virus is likewise 

 sometimes inherited to progeny through the eggs (53) (54). In such a 

 case the pattern of the virus is memorized by the germ cell and re- 

 covered when the egg develops into the adult. The pattern of a 

 virus, which has been impressed into a mother germ cell, must be 

 changed during the reduction of the cell to a gamete, so that the pat- 

 tern is present in the gamete only as a "memory" not as a complete 

 pattern. However, when the gamete develops to a certain extent fol- 

 lowing fertilization, the pattern is also developed to the revelation of 

 the virus. In such a case, the pattern of the virus may be impressed 

 in, and carried by, a certain gene, just as a normal pattern which 

 determines a normal character of the organisms. 



Every morphological and functional character, including organs 

 and tissues, are developed by numerous patterns memorized by each 

 gene in the germ cell. But peculiar environmental factors are re- 

 quired for their development. In the same way, a certain factor or 

 factors must be necessary for the development of a virus pattern. In 

 the case of cancers, sexual hormones may be at least one of the 

 factors. It was already stated that seasonal factors are important for 

 the development of the virus of measles (Chapter III, Part III). The 

 coincidence of the seasonal incidence of measles with that of the con- 

 ception of man, may suggest the involvement of hormones in both 

 cases. As previously detailed, hormones are, as a rule, required in 

 ontogeny for the development of organs and tissues. 



The predisposition to cancer must also be a memorized pattern of 

 a certain gene present in the germ cell, and the full pattern will be 

 raised in the individual developed from the germ cell when the proper 

 conditions are provided. When the pattern is revealed in the proto- 

 plasm structure of a cell, the cell is called cancer cell, and when the 

 pattern is stable enough to be retained in protoplasm fragments or 

 elementary bodies whereby the transmission of the structure to an- 

 other protoplasm is possible, the fragments may be called cancer 

 virus. It is considered, as above mentioned, that cancer cells may be 

 raised by the destruction of the mechanism by which the reduction of 

 somatic cells to primitiveness is inhibited. If this is the case, the 

 character tending to lose the mechanism are also to be borne by some 

 gene in the germ cell as a memorized pattern which will later develop 

 into the full pattern with the revelation of the character to lose this 

 inhibiting property in favour of the development of the proper pattern 



