126 Plant Tissue Culture 



wound (Haberlandt, 1913, 294, 1914, 295, 1919, 245, 

 296, 1921, 354, 1922, 355; Reiche, 1924, 369; 

 Wehnelt, 1937, 230; Bonner and English, 1938, 

 342; Sinnott and Bloch, 1941, 324) or by the in- 

 jection of such substances as the gall-inducing 

 secretions of certain insects (Kiister, 1911, 300). 

 Only the easiest types of materials have, up to the 

 present, been carefully studied. The field open to 

 future investigation is obviously very large. 



Summary 



Cultures may be started from seeds, from cut- 

 tings, or from excised fragments. In any case, 

 the final result must be a relatively uninjured, 

 aseptic mass of tissue, and the procedures for 

 obtaining such masses, either with or without the 

 intervention of chemical disinfectants, are of the 

 greatest importance. These procedures for ob- 

 taining aseptic seeds, adventitious roots, etc., and 

 for dissecting cambium and procambial tissues 

 are described and figured. Procedures for han- 

 dling other miscellaneous meristematic tissues are 

 also presented. 



