INTRODUCTION. 



devoured by insects of various kinds *. Plants preserved in her- 

 baria, especially if rare or local species, should always have the 

 time and place where they have been gathered carefully noted. 



Anatomical Study. The study of the Elementary Anatomy and 

 the Physiology of Plants opens up a far more extensive field for the 

 employment of instruments and technical manipulations. First 

 of all a compound microscope is an essential. For the student, 

 magmfyiug-powers of 1-inch, J-inch, and |-inch are amply suffi- 

 cient, although the more abstruse questions require the most per- 

 fect and powerful instruments that can be obtained. For general 

 students' use the binocular microscope has no advantage over the 

 ordinary instrument. 



The tissues of plants are observed for the most part by means 

 of extremely thin slices passing in various directions through the 

 structures. These are usually best made with a razor. Stems, 

 pieces of wood, and other firm objects, when being cut, may be 

 held in the finger and thumb of the left hand ; delicate and thin 

 structures, like leaves &c., should be placed between the two halves 

 of a split cork, or rolled round the edge of a cork, and the cork 

 supported by sticking it in the neck of a vial or test-tube, which 

 serves as a handle. Seeds and similar small objects may be fixed, 

 for slicing, on a piece of white wax. Where it is not imperative 

 to examine the tissues in situ, small portions may be softened by 

 boiling in water. 



Sometimes it is useful to obtain preparations by macerating the 

 softer tissues, either in water or weak acids. In the case of woody 

 structures recourse may be had to an operation which requires a 

 little care : a fragment of the wood should be placed in a watch- 

 glass with a morsel of potassic chlorate, to which a drop or two of 

 nitric acid is added by means of a glass rod, the whole being gently 

 heated for a minute or two, and water being poured on to prevent 

 complete solution. The fragments macerated in any of these ways 

 being placed on a slip of glass beneath the simple microscope, the 

 elementary organs may be picked out with a needle or extremely 

 fine camel-hair pencil, under a simple lens of J- or |-inch focus, 

 and removed to a clean slide. 



The thin slices, or the fragments of macerated tissues, should 

 be laid upon a slip of glass, a drop of water added* and a thin 

 glass cover laid on. They may then be examined under the com- 

 pound microscope. Objects of microscopic dimensions, such as 

 minute Algae, Fungi, pollen-grains, &c., require no preparation. 



* The mixture in use at the Kew herbarium consists of corrosive sublimate 

 one ounce, carbolic acid one ounce, methylated spirit two pints ; mix. It must 

 be used with great care, owing to its poisonous qualities. 



