530 Crown Gall-Animal Cancer Analogy 



differently stained cortex cells, and their study in series shows that the 

 surface of the tumor resembles a branching short root invading the cortex. 



November 3 was spent partly in " making photomicrographs of 

 No. 1188-62 crowngall on Ricinus petiole, showing invasion of 

 tumor cells in cortical parenchyma." By early December he was 

 concluding " There can be no question as to the growth of these 

 cortex tumors by apposition. The stimulating influence extends 

 out from the tumor on all sides about 1 mm." 



On January 13, 1921, he began to plan a paper on this subject. 

 His diary for the day read: " Continued making crowngall photo- 

 micrographs (tobacco cortex) to illustrate a projected paper on 

 manner of growth of the tumor. It is peripheral by apposition in 

 these particular tumors." His intention was, as he later ^^ ex- 

 plained to Professor A. Borrel of the Pasteur Institute, to add 

 " one more piece of evidence pointing to the cancerous nature of 

 the plant tumor, and I shall have," he hoped, " several additional 

 ones to add in the near future." By June 11 he had " read all 

 the more important literature pro and con of growth of tumors 

 by apposition and made copious abstracts especially from Virchow, 

 von Hansemann, and Borst." Three days passed and he was still 

 studying the " origin of small tumors in the pith of Tobacco cortex 

 tumor 1548D. They are close," he wrote in his diary, " to outer 

 tumor but not clearly connected to it; but they are in tissue which 

 I should call precancerous. There is a whole nest of little tumors 

 in this region, some very small and in some instances they have 

 caused the formation of a S7nall island of wood on the inner face 

 of strands of the inner phloem i. e., in the pith." For months he 

 had been examining various transition stages in the contact of 

 diseased with normal cells. A few quotations from his diary 

 indicate his precision: 



May 24, 1921. In all of the thousands of dividing cells I have never 

 seen a karyokinetic figure. I have thought that it was because I collected 

 them in p. m. and not at midnight or after, but I begin to think that the 

 cells may divide amitotically. At the border of the tumors ex[amine]d 

 today under high powers i. e., in the transition many of the nuclei are 

 notched or cleft deeply and a few wholly divided. I did not find the same 

 in nuclei of an embryo root or in the very fine-cells [of the] t[umor] 

 tissue. I will study further. 



"Letter, November 20, 1922. 



