234 
THE FRUIT 
end for scar showing where the pistil was attached. Scrape the skin or 
pinch it, and note the oil which shows as a yellow, odorous liquid. 
Note. Place a drop of this oil on linen paper. Note the spot it 
leaves. After a day examine the paper. Is the spot still visible? Oils 
that evaporate, leaving no spot, are called volatile or essential oils. 
Place peanut, Brazil nut, or castor bean on a linen paper. Heat till a 
clear spot shows. Lay aside and examine from time to time. Does 
the spot disappear? Oils that do not evaporate are known as true oils. 
Figure 218. — Cross Section of Orange, a Berry. 
A berry in the botanical sense is a fruit in which both exocarp and endo- 
carp are fleshy or juicy, although the seeds themselves, imbedded in the 
flesh, may be hard or even stony. Oranges, cranberries, huckleberries, 
currants, grapes, and tomatoes are true berries. A, rind; B, seeds; C, pulp. 
Make a cross section through the middle of the orange. How many 
distinct parts are there ? Where are the seeds ? Note the oil glands in 
the cut skin. Draw and label the parts named above. 
Remove the skin from a whole orange and separate the parts. How 
many are there ? Look for a strand of connective tissue on each one. 
Where do they come from ? Compare the number of sections with the 
number of vascular bundles on the stem end. 
210. Study of a Tomato. — Examine the whole fruit for 
traces of parts of the flower. On which end are they found ? 
How many sepals were there in the flower? Remove the 
stem and count the number of vascular bundles. Make a 
cross section through the middle. How many divisions in 
