A COMPARISON OF THE GROWTH OF MICE WHICH ULTIMATELY DEVELOP CARCINOMA WITH THE GROWTH.OF MICE UrHICH DO NOT DEVELOP CARCINOMA

Since cancer is a disease of growth, and its incidence in appreciable form is usually deferred until after the attainment of maturity, a very important factor in our ultimate understanding of the etiology of cancer must arise out of a knowledge of the degree to which the preceding development of the animal is dected by the ultimate aberration of growth. If the factors which determine the growth and incidence of carcinoma, for example, are of an essentially accidental character, such as local irritation plus infection, then the incidence of carcinoma in an individual will be decided in the main by factors not inherent in its habit of growth and metabolism, and the preceding normal development cannot be expected to foreshadow the impending pathological outcome. If, on the contrary, the incidence of carcinoma is determined by internal factors of growth-habit or metabolic peculiarities plus recurrent external factors, such as local irritation, then the underlying peculiarity of growth or metabolism may conceivably reveal itself in more or less marked departures from the average in the preceding normal development.