The History of Plant Tissue Culture 33 



not present in the nutrient might be essential for 

 continued growth. The work was dropped and 

 was not resumed by Bobbins for another decade. 

 Somewhat analogous studies were made by Cham- 

 bers in 1923, 43, 44, Mayer in 1929, 138, Heidt in 



1931, 50, and Malyschev in 1932, 53, 54. 



The ideas originally outlined by Haberlandt and 

 given their first really encouraging investigation 

 by Kotte and Robbins, passed then to other hands 

 and have seen considerable fruition since 1930. 

 Progress since that date has been largely under 

 the leadership of two workers, in France and in 

 the United States. Gautheret (Fig. 11), a stu- 

 dent of Guilliermond and disciple of Molliard, 

 carried out a great many investigations in the field 

 of "plant tissue cultures" in the years 1930-1940. 

 Studies similar to those of Kotte with excised root 

 tips were without marked success (Gautheret, 



1932, 48, 1933, 49, 95, 96, 1935, 15, 1937, 242, 1939, 

 97). But simultaneous studies using cambium 

 from large trees were much more promising. He 

 succeded in growing cambium tissues for con- 

 siderable periods (Gautheret, 1934, 67, 1935, 15, 

 1937, 68, 1938, 69, 70, 1939, 71, 72, 1940, 73), in pro- 

 ducing in vitro grafts (1935, 15, 1937, 16), and in 

 learning a great deal about the nutrient require- 

 ments of such tissues. With the work of his com- 

 patriot Nobecourt (Nobecourt, 1937, 74, 1938, 75, 



