The History of Plant Tissue Culture 29 



from the field of animal tissue cultures. Fibro- 

 blasts, when grown in culture, not only always 

 maintained their characters as fibroblasts, but 

 retained growth rates which were characteristic 

 of the particular tissues or organs from which 

 they had been excised (Parker, 1931, 421, 1932, 

 422-424, 1933, 425, 426). Epithelial cells also con- 

 tinued true to type (Ebeling, 1924, 389, 1925, 390; 

 Ebeling and Fischer, 1922, 391 ; Fischer, 1922, 403, 

 404, 1929, 408). These results conveyed the im- 

 pression that somewhere in the ontogeny of the 

 individual animal the potential capacities of the 

 cells had been segregated, only "fibroblast charac- 

 ters" being retained by fibroblasts and "epithe- 

 lium characters" by epithelium. This impression 

 has been so emphasized by much recent biological 

 work that the older concept of the cell as an " ele- 

 mentary organism" and the plant or animal as a 

 "society of cells" has fallen into disrepute and 

 has, to a considerable extent, given way to the 

 modern concept of the "organism as a whole." 

 The cell has come to be looked upon as a more or 

 less fortuitous structural element without any 

 fundamental importance except as one means out 

 of several by which the integrations of the whole 

 may be attained. 



There nevertheless remains much indisputable 

 evidence which seems to point to the importance 



