AIMS OF THE PRESENT WORK. 307 



overcome something of both disinclination and disqualification 

 for the work. 



In the third place, the plan of study here proposed recog- 

 nizes the importance in education of the element of time. The 

 very conception of mental unfolding as a growth implies, as we 

 have seen, an orderly succession of natural processes to which 

 time is an indispensable condition. Ideas are not only to be 

 obtained by observation, but they are to be organized into 

 knowledge. That this may be done effectually, so that acquisi- 

 tions shall be lasting, it must be done slowly and by numberless 

 repetitions. The plan of the First Book complies with this 

 condition by such a construction of the exercises as will secure 

 constant repetition and a thorough assimilation of observations. 



It complies with the time-requirement in another respect 

 also : it is but a first step, and involves many succeeding steps. 

 The mind grows, let it be remembered, for twenty or thirty 

 years, passing through successive phases, in which now one 

 form of mental action predominates, and now another. Every 

 study, which aims to cultivate any class of mental activities up 

 to the point of discipline, must extend through a considerable 

 part of this period. This is well understood with respect to 

 mathematics and Latin ; they run through from the ages of seven 

 or eight years to college graduation ; while three months is 

 the usual collegiate allowance of time for Botany. As the 

 true mode of treating the subject, both on its own account and 

 for educational purposes, requires that it be pursued in a 

 definite order through the whole school career, I have here 

 conformed to that condition by presenting only the first rudi- 

 mentary instalment of the subject. 



Fourthly and finally, the mode of study here proposed is 

 specially suited to call forth those operations in which grow- 

 ing intelligence consists. 



A child old enough to begin the study of Botany has 

 already acquired a large stock of ideas of concrete things and 

 their relations. As concerns plants, it has probably discrimi- 

 nated between leaves, flowers, stems, and roots. Its idea of a 

 leaf, for instance, though loose and indefinite, is still roughly 

 correct. The thin, green plate contrasts strongly with the 



