78 THE ENZYME TREATMENT OF CANCER
mammals, the occurrence of vagrant ones in various parts of the body, skin, pericardium, pylorus, rectum, liver, kidney, etc., would be as common a phenomenon here as in the fishes.
The germ-cells of vertebrates generally are, since 1900, beginning to be regarded as undoubted products of the egg-cleavage.* Since Wilms, Bonnet, Marchand, and Borst consider certain teratomata, at any rate, to be the offspring of cleavage-products, there would appear to be an identity between their conclusions and my own in this respect. Nothing could well be farther from the true facts. Taking Wilms as the leading exponent of the one side, the divergences between the two views work out as follows
By Wilms and others certain tumours, not by any means all, are referred to cleavage-cells, not identified as germ-ce11s, but really destined to form some part of the embryonic body. These cleavage-cells are “ shunted” from the normal connection at some very early, but not defined, period of the development. As so derived, they are parts of the organism in which they occur. Against the above, the writer’s conceptions may be stated in the following
Most, if not all, true tumours are pathological manifestations of some portion of a life-cycle, and they are due to abnormal attempts at development on the part of aberrant germ-cells, derivatives of the cleavage, and destined, not for the embryonic body, but for future generations. Such vagrant or persistent germ-cells are the sister - cells of the one by whose unfolding the “embryo” or individual arose, and, developing pathologically alongside and within another (sister) form,
* Compare the recent monographic works on Embryology by Korschelt und Heider, and by Waldeyer.