538 Crown Gall-Animal Cancer Analogy 



adduced to show that a considerable variety of organic acids 

 interfere with growth in plants/^ In both cases concentration 

 was critically important. 



Another laboratory technique which Smith used effectively to 

 advance his work was tissue cultures. He was among the first 

 American scientists to recognize the need and " the potential value 

 of a tissue culture technique in the study of plant neoplasia." *® 

 Dr. Philip R. White has said that he " did all in his power to 

 encourage the development of such a technique." The origins of 

 " the culturing of isolated fragments of tissues, especially of the 

 vascular plants, under controlled conditions " to enable workers 

 with more accuracy and completeness to observe plant life pro- 

 cesses, has been traced to Haberlandt and the last years of the 

 last century.*' Many biological students of plants and animals 

 have had a share in perfecting the method, including Dr. W. J. 

 Robbins of the New York Botanical Gardens. Smith learned 

 how to prepare tissue cultures for his work from an animal embry- 

 ologist, Mrs. Margaret Reed Lewis, who was then with the depart- 

 ment of embryology of the Carnegie Institution of Washington. 

 Her laboratory was then in Baltimore where her husband, Dr. 

 Warren Harmon Lewis, was professor of physiological anatomy 

 at Johns Hopkins University. On April 28, 1921, Dr. and Mrs. 

 Lewis had called on Dr. Smith in his laboratory at Washington. 

 After examining slides of crown gall, they were given by him 

 cultures of Bacterium tumefaciens. Smith had been acquainted 

 with Dr. Lewis for some years, having met him at the Marine 

 Biological Laboratory of Woods Hole while the latter was studying 

 under Dr. Franklin P. Mall. Their plan in 1921 was to secure, if 

 possible, tumorous overgrowths in chickens by cultural inoculation 

 of Bacterium tumefaciens, and, by means of tumor transplantations 

 to other chicks, to prepare tissue cultures and study the possi- 

 bilities of viruses and toxins in the culture media. 



In March 1922 it was thought that an animal tumor had 



media with various organic and inorganic sources of nitrogen, Amer. Jour. Bot. 35: 

 227-238, at 230. 



^^ A. C. Hildebrandt and Riker, The influence of various carbon compounds on 

 the growth of marigold, paris-daisy, periwinkle, sunflower and tobacco tissue in 

 vitro, idem 36(1): 74-85, at 78, Jan. 1949. 



** P. R. White, Plant tissue cultures, Ann. Rev. of Biochemistry 11: 624, 1942. 



*'' P. R. White, Plant tissue cultures. The history and present status of the prob- 

 lem, Archiv f. exper. Zell. bes. Gewebz. 10: 501-518 at pp. 502, 511, 1931. 



