Fl'kthir Ri si;aiu:hi:s in Disi:asi:s of Plants 539 



resulted from inoculations with the crown i;all organism, but, the 

 tumor receding, Mrs. Lewis on March 30 reported to Dr. Smith: 



My plans liavc failed owing to the t.Kt that all of the overgrowths 

 obtained with the new cultures of bacillus tumcfacicns from the peach and 

 from cuonymus have been absorbed aqain. There was quite a marked 

 enlars;cment in some cases but it lasted only a tew days. The cells which 

 contain the organism after it has become changed resemble the human can- 

 cer cells. I inoculated several dozen developing eggs also and in every case 

 where the embryo survived, I was able to recover the organism from the 

 liver, after three or four days. A number of the embryos had malformations 

 of the head. . . . The important point is to get the organism inside of the 

 cells without any accompanying reaction of the tissue against them. 



An enclosed memorandum ended: " Very diflicult to stain 

 organism without destroying all cytological structure of the cell." 

 Again in 192"^ these experiments were to be tried on rats and 

 rrogs, but result in only one " small tumor in the lymph sack" 

 of a frog. Again in 1926 Smith was to repeat some experiments 

 on salamanders and reexamine, in the light of new experimental 

 disclosures from Germany, whether several years earlier he, when 

 he tried similar experiments, had erred in any research particular. 

 From a series of inoculations with Bacterium tmyiefaciens, he had 

 obtained but one seemingly definite salamander carcinoma. 



By 1921, and even before then. Bacterium tumefaciens was 

 being recognized as a carcinogenic agent of more than ordinary 

 significance. In April 1922, when he decided to consult cancer 

 research specialists before completing his paper (and address) 

 on appositional growth in crown gall tumors and in cancers, he 

 went first to Baltimore where Mrs. Lewis showed him tissue 

 cultures from their first set of inoculations with the crown gall 

 organism. His diary of April 17 reveals that he found them 

 " indistinguishable from reactions and similar cultures (ectoderm) 

 inoculated with two or three cancer cells. She is to gvjt me cultures 

 of an organism (rod) she obtained from a Sarcoma and I will try 

 it on plants." April 18, he wTOte: " Mrs. Lewis showed me addi- 

 tional cancer preparations. Whether (l) Bacterium tumefaciens 

 is used (2) an organism from cancer, or (3) a few cancer cells 

 or (4) Rous's chicken sarcoma ground, in her tissue cultures, there 

 is the same type of reaction viz. small and deeper staining cells 

 (3 or 4 times closer together) with notched nuclei. Material 

 stained at end of 48 hours or sooner." April 27 he learned " how 



