CHAPTER III 

 THE DEVELOPMENT OF CANCERS 



1. The Reduction of Protoplasm to Primitive Structure 



Since all the somatic cells have their origin in germ cells, all 

 kinds of somatic cells, if their structure is reversible, should be re- 

 duced to primitiveness of germ cells when a suitable stimulus is given 

 under a proper condition. In fact, as pointed out in Chapter I, the 

 reduction tends to occur without difficulty in some lower animals and 

 generally in plants, so that regeneration is common among these or- 

 ganisms. In higher animals, however, the reduction is not so common 

 and it appears that some mechanism must have been developed be- 

 cause the reduction is unfavourable for these organisms, but occasion- 

 ally this mechanism appears to get out of order, resulting in the 

 occurrence of the reduction in some somatic cells. 



The reason why cancer cells are developed from the somatic can 

 be explained in this way. It is a well known fact, as will fully be 

 described below, that cancer cells are of a primitive nature comparable 

 to that of germ cells. The production of cancer instead of germ cells 

 may be due to the incompleteness of the reversion of the primitive 

 structure probably because of the presence of the mechanism to pre- 

 vent the reversion. 



Hormones, especially sexual ones, appear to be involved in the 

 production of germ cells ; sexual hormones may be the main factor 

 providing the environment under which the reversible change of the 

 somatic cells to gametes is established. In short, hormones may be 

 factor X which converts A'" to A in Fig. 34. In this connection it 

 should be mentioned that, as is well known, sexual or other related 

 hormones are intimately connected with the development of cancer cells. 

 This suggests strongly that the production of cancer cells is carried 

 out by the same principle as that of germ cells. It is believed by the 

 majority of workers that hormones or hormone-like substances may 

 be produced in the wound regions of plants where the primitive cells 

 are induced to achieve the regeneration. It is well conceivable that 

 mechanical injuries will result in the formation of certain hormones 

 which cause the production of the primitive structures comparable to 

 cancers. 



