Prospects • 139 



both meristems and other tissues with the most sensitive cyto- 

 chemical and other microscopic techniques. Ideally, this sort of 

 work could provide suggestions as to what biochemical changes to 

 investigate with grosser methods. Even relatively traditional ana- 

 tomical studies can give important information on the action of 

 various growth regulators (for example, Sachs et al., 1959, 1960) 

 and it would seem highly desirable to have such information as 

 closely correlated as possible with that gained from other ap- 

 proaches. Even some very simple-minded questions might have 

 valuable answers: What are the differences, if any, in intracellular 

 organization or content between induced and noninduced Perilla 

 leaves, and how soon do they arise? During the time that florigen 

 is believed to be moving from an induced leaf to a meristem, can 

 changes be observed along its route? And so forth. 



In short, the field will undoubtedly continue to progress as it 

 has in the past— through critically tested guesses, appropriate choice 

 of experimental material, perseverance, and technical advances. It 

 is obvious by now that the writer has no revolutionary improve- 

 ments in approach to propose, which is hardly surprising since 

 differentiation and development have yielded their secrets slowly 

 to better minds than his. But the progressive understanding of 

 these problems, representing as they do much of what is contained 

 in that simple word, "life," is surely an enterprise worthy of 

 the best. 



