THE CANCER PROBLEM 117
development, like the trophoblastoma of chorio-epithelioma, nourishes itself by an (intracellular) acid digestion. A malignant tumour, a cancer or sarcoma, nourishes itself in exactly the like manner. Like the trophoblast, it eats and erodes its way, destroying tissues by an (intracellular) acid digestion. Only by such could a cancer erode bone.* To describe in detail what should follow would be to recite much of two papers** published long ago as well as some other points noted since that time. The solution of the question is possibly the resolution of the problem of cancer. The mammalian embryo solved this ages ago ; indeed, it “ inherited” the solution from “ancestors “ much lower down in the scale. The very existence of “the embryo” throughout the higher animals is dependent upon the suppression, the degeneration and death, of the asexual foundation upon which it came into being. In many invertebrata the sexual generation eats up (often by phagocytes or wandering cells) the asexual foundation or “larva”; and it must be recognized that in the higher forms it practically digests it. On the present occasion no account of the work required to establish it need be given ; much, not all, of it is contained in my published memoirs. The fact may be stated briefly that in fish and mammal alike it is the
* This remark about the power of cancer to erode living bone was a trap for the unwary, deliberately set by the writer. As had before happened, it caught its victim with certainty; for at once it was asserted, as I had often before heard it, that the wall of an aneurysm could erode bone also—thus, the vertebral column— and did I therefore mean to suggest that this was an acid-erosion, etc. ? The reply to this is, that the pressure of the aneurysm here kills the bone, and that the dead, not living, bone is then removed by the agency of some enzyme of the leucocytes or white blood-cells.
** Beard, J.: ‘Certain Problems of Vertebrate Development,” 1896, and the” Span of Gestation and the Cause of Birth,” 1897, both published by Dr. Gustav Fischer, Jena.