APPENDIX ON PRACTICAL WORK. 171 
united at base. Carpels, generally 3. Placentation, axile. Fruit, 
a capsule (fig. 69, G). 
Exs,—Harebell, Canterbury bell. 
I].—Anatomy,—Root p. 14). Stem (p. 29).—Try to follow, mainly 
by longitudinal slicing, the course of the bundles im a piece of aspara- 
gus stem (ef. fig. 5, C). Leaf—The distribution of vascular bundles is 
plainly seen in most herbaceous forms, and may be rendered still more 
plain by bleaching in spirit, and then soaking in chloral hydrate. 
Compare the distribution in monocotyledons and dicotyledons. 
III. Histonocgy.—A compound microscope is necessary for this. 
Browning’s field-microscope, shown in fig. 70, will answer the purpose 
tor a beginner, and even if 
a larger microscope is after- 
wards purchased, will always 
be useful for carrying about. 
It consists of a stand, eyepiece, 
and objectives. The stand is 
supported by three legs, and 
carries a sliding tube above, 
and a perforated plate or 
stage below, upon which the 
object to be examined is 
placed. Below the stage 
swings a small concave mir- 
ror, from which light can be 
reflected upwards through 
- the aperture. The eyepiece 
slips into the upper end of 
the tube, while the objective 
screws into the lower end, Objectives are named, according to the 
distance at which they must be placed from the object, two inch, 
inch, half-inch, quarter-inch, &c., &. Inch and half-inch objectives 
will be sufficient for elementary purposes, and will be called low power 
and high power in the rest of this Appendix. The price of Browning’s 
field-microscope, with one eyepiece and the two objectives named, also 
with case and forceps (as in figure), is £2, rs. 6d. Suitable glass slips 
(say two dozen) and cover-glasses ($ oz. of small squares) can be obtained 
for a small sum of the same maker.? 
We may examine objects in two ways: (1) by reflected light ; (2) by 
transmitted light. It is perhaps easier to commence with the former. 
(1.) Opaque objects are best suited for viewing with reflected light. 
Pollen grains (preferably of mallow or hollyhock), small seeds, or flat 
bits of leaf with hair structures are good examples. Place one of these 
objects on a piece of black paper on the centre of a glass slip. Screw 
on the low power, and pull out the inner half of the microscope tube 
till a groove upon it is seen. Put the slip under the two spring-clips of 
the stage, and turn the mirror so that it reflects no light through the 
hole. To focus, slide down the tube near to the object, apply the eye to 
the eyepiece, and slide up the tube till the object is seen. ‘This sliding 
action is the coarse adjustment. The fine adjustment is brought into 
1 63 Strand, London, S.W. 
