IV PREFACE. 



" But if we endeavour to seize the floating conceptions furnished by 

 common experience, and to fix and define them by a course of exact 

 practical observation of the more accessible characters of plants (showing 

 the relations of these as they occur in different divisions of the Vegetable 

 Kingdom), we place the student in a position which enables him to pro- 

 ceed at once with an inquiry into the peculiarities of the plants he 

 meets with, and in this way to acquire a fund of practical knowledge, 

 which is not only absolutely requisite before entering on abstract in- 

 quiries, but is especially calculated to secure his permanent interest in the 

 study. 



" Physiology is undoubtedly of the highest importance, and from its 

 nature is that part of the Science which, were it not for the above diffi- 

 culties, would with most advantage be taught by Lectures. If the 

 previous education of medical students prepared them, as it should, with 

 an elementary knowledge of the Natural Sciences, we should make 

 Physiology the most conspicuous feature of a course of Botany in a 

 Medical School. In the mean time we subordinate it to the other branches 

 in practical teaching, and in this volume have dealt with it in what we 

 regard as its proper place in the order of study." 



Since these remarks were written, and owing in part to the 

 advances made in the Science o Vegetable Physiology, the subject 

 has received more attention in this country, while at the University 

 Examinations greater stress than heretofore is laid upon it. How- 

 ever desirable in one sense this may be, it is at present objection- 

 able, because few or no means are open to the average student of 

 making himself practically familiar with Experimental Physiology. 

 Moreover, the skill in manipulation and microscopical observation 

 required for anatomical or physiological investigations cannot 

 possibly be acquired in the few months devoted to the subject 

 by the majority of students and candidates for examination in the 

 Scientific and Medical Faculties. Sooner or later these defects 

 in the practical teaching of Physiology will doubtless be remedied, 

 In the mean time, practical tuition in Morphology and the rudi- 

 ments of Classification appears to be the best and most ready 

 method of training a student to observe, to reflect, and to classify. 



