^28 APPENDIX. 



for ex'^mination with high powers is difficult, but with 

 some practice it can usually be well done. For this 

 purpose a razor is used. The object or specimen to be cut 

 jjs held between the thumb and fingers of the left hand ; 

 if it is delicate or thin, as a fragment of leaf or piece of 

 wood, etc., it can be cjamped iija islit piece of elder pith, 

 or of cork. The section must be made exactly at right 

 angles to the longitudinal axis of the stem, leaf, etc., 

 and the knife or razor must be drawn with the right hand 

 steadily (better feather quickly) and obliquely to the blade 

 towards the person. -A drop of water or alcohol should 

 be placed on the blade before cutting, in which the sections 

 can at once fioat ; if they become dry, tibey are worthless. 

 After making very many eectioQS, thr«e or four of the best 

 ones can be carefully lifted with the point of a scalpel^ 

 mounted needle, or otherwise, and transferred from the razor 

 to the glass elide, previously cleaned and wiped with care, 

 and on which a drop of the mounting fluid has been 

 placed. Over these place a clean cover-glass, and remove 

 any superfluous fluid which may be at the edge of the 

 cover-glass with a piece of bibulous paper. Then the 

 object is ready for examination; place it on the middle 

 of the stage and move the tube of the micsroscope down till 

 the objective is supposed to be at -about the proper point 

 for clear vision. Then look through the eye-piece, and at 

 the same time move the mirror until it is so adjusted as to 

 reflect the proper amount of light up Uirongh the specimen. 

 Now with the fine adjustment focus accurately and ex- 

 amine the object ad libUmm. Sketch what is seep, which 

 will be both a test as to correct observation and a means 

 of better fixing the image in mind. 

 332. Mounting specimens for preseryation and snbee- 



