WHAT BOTANY IS OF MOST WORTH ? 35 



morphological instinct. It consists both in a power 

 to compare a series and eliminate what is individual 

 and unimportant from what is common to a number 

 and important, and also in a power, by comparison 

 of different stages of development, to trace back dif- 

 fering forms to their common origin, or similar forms 

 to their different origins, as the case may be. For 

 training in this power, so important in all phases of 

 human activity, nothing is better than morphology, 

 the introduction to which is best made through forms 

 which are large and plain enough to need no tools, 

 but only the unaided eye and thought. For this the 

 embryos in seeds, which show homologous parts under 

 the greatest diversity of size and form, are particularly 

 good, especially since they may so easily be traced 

 through stages of germination and growth where 

 actual proof of their analogies and some of their 

 homologies may be found. Best of all for morpho- 

 logical training, and most used, are the shoot (leaf 

 and stem), root, flower, and fruit, of the higher plants. 

 It is true that minute plants also offer extremely good 

 materials for morphology and anatomy, but they re- 

 quire the use of unfamiliar tools and methods, and it 

 is better at first to use materials in which the atten- 

 tion need not, by purely mechanical conditions, be 

 distracted from the real problems. 



Next among scientific instincts comes faith in cau- 

 sality, involving the belief that every phenomenon is 



