60 THE ENZYME TREATMENT OF CANCER
originally taken up by them, and it has often been noted how they would appear to be hustled about from pillar to post, when in the way, until they land in some corner or other. Normally, if the paradox be allowable, the development of such a vagrant germ-cell should result in a more or less complete twin-embryo; but any gradation of this down to a very rudimentary embryo may be found in practice. Figured in Ziegler’s” Pathologie” may be seen all sorts of steps, from complete identical twins, only abnormal in being united at some point, through those more completely united, to others forming more or less complete embryos, embedded within or projecting from a normal one, down to mere cysts or absolutely rudimentary embryos.* No one has ever witnessed the development of such a rudimentary embryo or embryoma, and probably it will never be seen; but the connection between them and vagrant or persistent (in ovary or testis) primary germ-cells is not less certain than that between an onion and the seed originally planted. In the same way, the hypothesis that the vagrant primary germ-cells of certain regions — thus those of the neighbourhood of the stomach and of the rectum—if they develop, give rise, not to an embryo, but to an asexual generation of indefinite unrestricted powers of growth, can never be converted into a fact by direct observation. It can only be inferred from the facts. But it is a very simple explanation of all the facts, and its probability is increased by other considerations.
But why should a vagrant germ-cell, when developing into a cancer, omit or skip the formation of an embryo, and proceed with a different portion of the life-cycle?
* A much fuller series of such embryonic monstrosities, forming a very interesting and instructive collection, will be found in Ernst Schwalbe, “Die Morphologie der Missndungen,” etc., Part II., Jena, Gustav Fischer, 1907.