FRUITS AND COLONISATION BY SEED. 39 



needles of calcium oxalate, which will wound the lips 

 and tongue of any animal eating the fruit, if it has not 

 sufficient intelligence to extract the juicy part within. 

 These needles are probably intended to keep off slugs 

 and snails, and perhaps also small rodents which would 

 devour the seeds. 



For practical fruiterers this defensive bloom is of the 

 greatest importance. Bruising the fruit should be care- 

 fully avoided. For example, in packing oranges for 

 transport, every fruit should be rolled in thin paper to 

 prevent destruction of the peel. Even an almost 

 imperceptible abrasion on the skin of an apple, permits 

 bacteria to enter and cause decay of the flesh.^ 



(2) The colours of fruits are, like those of flowers, 

 imperfectly understood. If paper letters are fixed on 

 an apple whilst it is young and green, the shaded parts 

 do not turn red, which shows that the colour depends, 

 partly at any rate, on the fruit being acted on directly 

 by the sunlight. The colour varies greatly, but it is 

 nearly always very conspicuous. Red is the most 

 usual, as is seen in the Hawthorn, Rose, Rowan, and 

 other plants. Yet these reds are not the same. They 

 vary in shade, and always contrast beautifully with 

 the special green of the leaf The Rowan green is not 

 the same as that of the Rose, and the red varies accord- 

 ingly. Yellow is often found. Deep black occurs in 

 the Olive, which is set off by the shining white twigs. 

 Blue or blue-purple occurs in the Herb Paris, and 

 among the members of the Solanaceae. Besides its 

 pleasing colour, fruit has also very often an attractive 

 perfume. 



(3) The origin of the sugars and fruit jellies is not 

 difficult to understand, at least in a general way, for 



^ The experiment is easily tried and most instructive. 



