112 THE ENZYME TREATMENT OF CANCER
in the pre-critical period the staining of the trophoblast cells resembled that of the functional transient ganglion cells—with methyl-blue eosin they took on an exquisite blue stain. With the passing of the critical period the cells of the trophoblast, as Hill has shown for the bandicoot (Perameles), no longer took on the blue stain, but absorbed ever more and more the red eosin. The like change will be noticed in the transient ganglion cells of the fish; it is also seen in the merocytes* of the yolk.
Rather less than two years ago I really commenced to work at the problems of malignant neoplasms from their embryological aspects. The starting-point for research here was obtained from certain results of prolonged investigations into the mode of vertebrate development. From these it had been established beyond question that in the normal life-cycle of development in any of the higher animals there were two generations—an asexual one, the “larva,” or phorozoon, and a sexual one, “the embryo “—that the former was mainly; if not entirely, represented in mammalian development by the trophoblast, and that in every normal development the trophoblast was suppressed by the sexual generation, its degeneration commencing at the critical period with the completion of all the parts of the embryo. For the past eight years it had been recognized that at the critical period a change in nutrition always occurred. In 1902** the conclusion was advanced that cancer was an irresponsible trophoblast, the continued and unbounded
* “Merocytes” are certain curious nuclei, or, perhaps cells, with no particular cell-substance around them as a rule, which occur in the yolk-sac of many fishes. Often they are much elongated and branched, due to incomplete cell-divisions (pluripolar mitoses). Apparently they are asexual structures. The writer has, as yet, not published all his observations upon these merocytes.
** The Lancet, June 21, 1902, p. 1758.