Malignancy of the crown gall and its analogy to animal cancer
Experimental biology and medicine
METHODS EMPLOYED I N THE INVESTIGATIONS In 1907, Dr. E. I?. Smith showed that the disease of plants called crown-gall-tumor-like in nature-could be reproduced artificially by an inoculation of a normal plant with a pure culture of a bacillus which he called Bacterium tumefaciens. Smith maintains that this or a similar disease can be produced only by this particular organism, that all other tumor-like formations observed in plants due to other parasites, like Plasmodiophora brassicae, are
... y different pathological entities, and that only crown-gall is a true plant tumor. In his estimation, this tumor is practically identical, biologically, with animal and human cancer. Since crown-gall is caused by the action of the bacterium described by him, he concludes in one of his recent articles that to a biologist the conclusion is almost irresistible that human cancer must be due to a parasite and that one parasite may well be the cause of the most diverse forms, as we have seen t o be the case in plants." This deduction is so sweeping in character, so far-reaching in its generalization, and the results of Dr. Smith's work have become so widely known and quoted by the medical profession that it has seemed to the writers to be desirable to renew his investigations, to analyze the material from the viewpoint of animal pathology, and to attempt to determine the true analogy between the crown-gall and animal cancer.