5o6 Home Nature-Study Course. 



LESSON LXVIII. 



THE FRUIT. 



Purpose. — To lead the pupils to see for themselves the seldom 

 noticed peculiarities of these fruits. 



First study the fruits entire; observe the differences in shape and 

 color, not only between orange and lemon, but also between the different 

 varieties. Notice the little depressions and pin-like dots over the surface 

 of all the fruits. Shave off a bit of the outer, yellow part of the rind, 

 double it together and pinch it hard ; a fine spray flies from it into the 

 air, and a strong fragrance is noticeable. If the spray is made to fall on 

 paper it makes a " grease spot," and if on water drops of oil are visible, 

 but this oil is extremely volatile and soon passes into the air. This oil 

 in the rinds of lemons and oranges is extracted and used for flavoring. The 

 russet color on the Florida oranges is caused by a mite almost invisible, 

 which feeds on the oil. It was formerly confined to Florida but has been 

 introduced from Florida to the lemon groves of southern California; see 

 p. 285, "Yearbook" of the United States Department of Agriculture 

 for 1900. 



Note the stem end of the fruit. If there is a button or stub still 

 clinging pick it off ; observe that there is a circle of dots beneath it. 

 These are the tips of fibers which held the fruit to the stem ; they pass 

 through the fruit from stem to blossom end as may be seen in cross 

 section. 



Cut the fruit in cross section and note that the rind is made up of 

 several layers ; the outer yellow skin ; the layer of oil cells ; then a thick 

 white layer next to the pulp. Note that the juicy pulp is divided into 

 radiating sections. Peel an orange and pull apart the sections ; note how 

 many there are and the thin membrane which covers them. Break one of 

 these sections and separate one of the cells containing juice and examine 

 it. This is an instance of very large vegetable cell, and may be used to 

 illustrate the cellular structure of all plants, although it should be borne 

 in mind that these cells are developed for juice sacs, while ordinary living 

 vegetable cells contain the growth-making materials of plants. Do the 

 number and size of the sections differ in the lemons and oranges? Does 

 the rind of these two fruits differ in taste as much as does their 

 pulp? Where are the seeds placed? Note the tough skin in which the 

 white, starchy meat of the seed is wrapped. Take a seed apart and 

 discover the germ or sprout ; taste the meat of the seed and note how 

 bitter. Might not this bitter taste have been an advantage to the wild 

 orange by causing animals which like the pulp to reject and scatter the 

 seeds? Note that all oranges do not have seeds. This is because man 



