540 Crown Gall-Animal Cancer Analogy 



she makes tissue culture"; and, on May 13, after several times 

 working together, he placed the following comment in his diary: 

 " By injecting the heart of a chick embryo with Bacterium tume- 

 jaciens (peach strain) and then at once starting tissue cultures 

 from a bit of the peritoneum she has a tissue culture with giant 

 cells and also with abnormal masses that look like a roundcell 

 sarcoma. She is a genius! " 



After he had adapted the tissue culture technique to the study 

 of plants, he brought his first plant tissue cultures to her/^ 

 Together the Lewises and he interested Dr. D. S. Johnson, pro- 

 fessor of botany at Johns Hopkins and a friend of Dr. Smith, 

 in perfecting the procedure. Later Miss Nellie A. Brown of Dr. 

 Smith's laboratory learned from Mrs. Lewis how she prepared 

 tissue cultures.*^ About 1924 Dr. Johnson suggested that his 

 brilliant student, Philip R. White, be placed at work on the subject 

 as a specialty. He spent the summer of 1929 at the Mt. Desert 

 Island Biological Laboratory at Salisbury Cove, Maine, studying 

 the methods of Dr. and Mrs. Lewis in their laboratory quarters.^" 



Since Smith's years, tissue culture methods have greatly aided 

 scientists in studying problems of organic metabolism. By this 

 procedure, not only interesting confirmation of his earlier beliefs 

 about growth stimulations and inhibitions by acids has been pro- 

 vided, but also the study of acids and their influence has been 

 directed toward determining their effects on host plants and the 

 bacterial organism. ^^ Smith helped to advance the work, especially 

 by his efforts to determine with exactness the factor of pH or 

 hydrogen-ion concentration in plant tumor growth.^- Years were 

 spent by him in investigating growth-promoting, growth-regu- 

 lating, and growth-retarding substances. So far as this author is 

 aware, the word " phytohormone " was never used once by him 

 in his v/ritings. The vast, organized study of plant hormones, as 

 such, postdated his years of research. Yet the subject matter now 

 embraced by hormones and their effects is an integral part of 



** Told the author by Mrs. Lewis. The Lewises were then still living in Baltimore. 



*° Told the author by Miss Brown. 



^^ White, Plant tissue cultures. The history, etc., op. cit., 511. 



^^ A. J. Riker et al., works cited; also, memorandum by Dr. Riker to the author. 



°^ A. J. Riker, Studies on the influence of some environmental factors on the 

 development of crown gall, jour. Agric. Res. 32: 83-96, 1926; also, Amer. Jour. 

 Botany 32: 357-361, 1945. 



