A.-APPENDIX ON PRACTICAL WORK. 



The importance of practical work in Natural Science is now universally 

 admitted, and it is therefore unnecessary to enlarge upon it here. This 

 book is mainly written for students who are anxious to verify the lead- 

 ing facts of Botany, and, in accordance with this end, common plants 

 have been used wherever possible for purposes of illustration. 



Practical work in Botany may be considered under the following 

 headings : — I. Description of Plants ; II. Anatomy ; III. His- 

 tology : IV. Physiology. 



I. Description op Plants. 



We are here mainly concerned with the external features, and the 

 apparatus required is of the simplest description : (i.) A sharp pen- 

 knife is necessary for cutting through stems, buds, flowers, ovaries, &c, 

 in various directions (pp. 29, 30, 74, 84, and fig. 48). (2.) Dissecting 

 needles, preferably three-sided glovers' needles, mounted in handles, 

 serve for separating out the individual parts of small flowers, &c. 

 Pieces of fresh twig form useful handles. The blunt ends of the 

 needles are pushed into the pith, and, after a few weeks, contraction of 

 the wood will have fixed them firmly. (3.) A botanical lens is essential 

 for examination of the flower. Without it the placentation (p. 104), 

 among other things, could not be made out in small flowers. A three- 

 fold lens, such as opticians sell for about 3s., is the best form. For a 

 small sum a stand for this can be obtained, consisting of a vertical rod 

 fixed below to a heavy foot-stand. A hole is bored in the fittings of 

 the lens just large enough to admit the rod, and allow of sliding up and 

 down. Both hands are thus left free to dissect with needles, or other- 

 wise, small objects placed on a sheet of white paper. The sliding action 

 permits accurate focussing. It may not be superfluous to point out the 

 right way of using a lens. It should be brought close to the eye, and 

 then near the object, taking care to have a good light. Beginners fre- 

 quently place the lens near the object, and then try to look through it 

 from some distance, as if they were inspecting a photograph through a 

 large magnifying-glass. (4.) Small pins (sold in shops" as " minikins ") 

 are useful for fixing down the parts of a flower in the form of a diagram. 

 A piece of thin deal board affords a convenient basis. (5.) A pair of 

 small brass botanical forceps will be found extremely useful, perhaps 



*45 K 



