INTRODUCTION. 3 



In the present work, the different departments are treated of in 

 the following order : 



Part 1. MORPHOLOGY, or COMPARATIVE ANATOMY or PLANTS. 

 2. SYSTEMATIC BOTANY. 3. PHYSIOLOGY, including PHYSIOLOGICAL 

 ANATOMY. 4. G-EOGRAPHICAL and GEOLOGICAL BOTANY. 



SECT. 2. METHODS AND MEANS USED IN THE STUDY 

 OF BOTANY. 



Examination of Plants. The study of the morphology of plants, 

 to which the first Part of this volume is devoted, necessitates little 

 more than a supply of fresh specimens, a penknife, two or more 

 needles mounted in handles, and a pocket magnify ing- glass of 

 moderate power. One of the needles should be of the ordinary 

 form, and others with a flat top with a cutting-edge like a 

 hare-lip pin. Roots, stems, and leaves require little or no prepara- 

 tion ; and the dissection of most flowers is a very simple operation. 

 The majority of the characters of many flowers may be observed by 

 simply removing successively the parts with a penknife, and by 

 examining them in perpendicular and cross slices. In any case care 

 should be taken to detach and observe the parts in regular order, 

 so as to ensure an accurate knowledge of the way in which the 

 different parts are arranged. Perpendicular sections of entire 

 flowers made through the centre and from below upwards are very 

 instructive ; and horizontal sections through unopened buds, both 

 of leaves and flowers, are likewise necessary for the examination of 

 the relative position of the organs and of the way in which they 

 are packed. When flowers are extremely minute, and also for the 

 investigation of the structure of ovules and seeds, a pocket-lens 

 mounted on an upright bar, or a simple microscope, becomes requisite. 

 The latter instrument consists essentially of a stand, provided with 

 a movable arm supporting a magnifying-glass over a stage upon 

 which the object is laid, so that both hands may be at liberty for 

 its dissection. The stage is an open frame, upon which a slip of 

 glass rests ; and the object to be examined, lying on the glass 

 slip, may be illuminated by a small mirror beneath sending light 

 through it, or, if required, by a condensing-lens at the side bring- 

 ing a bright spot of converging rays upon it. The dissection is 

 effected with a fine dissecting scalpel and needles. By their means 

 the parts of the flower can be separated one from another so as to 

 show their numbers, form, combination, and position with regard 

 one to another. 



In pursuing the study of Systematic Botany, the same means 

 are used, the only difference being that the investigation of each 



132 



