Studies on cancer. III. Cellular growth and degeneration in the organism.

Abstract

As it is well known an active independent growth of cells in the body is peculiar alone under normal conditions to the earlier periods of development. At first this growth is quite generalized. Later it becomes localized, first in one part and then another. In man it ceases entirely with the laying down of the last kidney tubule and glomerulus at about 10 days after birth. Subsequent to this time all growth is merely the enlargement of pre-formed organs and tissues. It is like the hypertrophies and hyperplasias of later life.

In later life it is again well known that hypertrophy and hyperplasias are related directly to the functional activity of the part. Increase the work of the heart, it grows. Decrease its activity, it atrophies. So, in the same manner, the removal of a part of any organ or another organ of the same kind leads to an active enlargement of the remaining parts. This enlargement continues to the re-establishment of a certain size which corresponds to the functional demand made upon the part.

As a moderate increase in the functional demand made upon an organ or a part is associated with the growth of that organ or part so further or excessive work is associated with a degeneration of these same cells. Such a degeneration is also seen in certain structures during development. The pronephros and the metanephros of higher animals suffer such changes as they give way for the development of the kidney.

Cancer represents a return of the property of independent active growth to certain cells or rather to groups of certain cells in the organism. This independently growing tissue also often suffers extensive degenerative changes in part. While these degenerations resemble ordinary autolytic changes they differ from those seen in the infarct, for instance, in that they are not harmful for the organism.