Abstract
Crown gall is an infectious disease of plants which may be induced artificially by inoculating with the aid of a needle prick of a drop from an agar culture of Bacterium tumefaciens. Erwin F. Smith, of Washington, who investigated the condition continually for the last 10 years, is of the opinion that the disease is identical with human cancer. Irrespective of the stand one takes in regard to the identity of the two conditions, it must be conceded that there is a great deal of analogy between them. Crown gall as well as cancer is a new growth caused by a continuous, limitless proliferation of a group of cells within a tissue which normally do not proliferate at all. As a result of the rapid proliferation the new cells remain young and undifferentiated.
Clinical and experimental evidence indicates that the main biological and therapeutic action of X-rays consists in inhibition of the proliferating power of young undifferentiated cells. In man and vertebrates the mechanism of the action of X-rays on tumor cells is obscured by the changes in the cellular elements of the blood, lymph and the fixed connective tissue cells of the surrounding regions which is always encountered side by side with the changes in the tumor cells themselves. The crown gall, on the other hand, is an ideal subject for the study of the direct biological action of the X-rays on the tumor cells, since there is no other tissue present which may be changed by the rays.
For the present study ricinus plants and agar subcultures of Bacterium tzimefaciens were used. The seeds for the former and the primary culture for the latter were obtained through the courtesy of Dr. Erwin F. Smith.
Get full access to this article
View all access options for this article.