692 THK FIBRO-VASCULAR SYSTKM OF THE QUINOK, 



elongated, and expanded transversely. Then at the junction of 

 this layer with the pulp-cells, the vascular bundles constitutino; 

 the plume-like branches spread out in a dense mass horizontally. 

 It' this is taken in conjunction with tlie naked-eye appearance of 

 the plume-like filaments, as they appear when the skin is removed 

 from a rotting quince (Fig. 12), there are good grounds for believ- 

 ing that the cells there are matted together by the permeating 

 vessels, and that the tissue is tough in consequence. 



If we turn to the chemical composition of the ash of the respec- 

 tive fruits, some of the constituents are seen to be in very different 

 proportions, which may throw some light on the difference of tex- 

 ture. 



The following analyses are taken from Dr. Griffiths' "Manures 

 for Fruit and other Trees" (1908) :— 



Percentage chtmical comjiontion of the ash. 

 A pple. 



PotashiK^O) 56-21 



Soda(Na„6) 14-02 



Lime(Ca6) 4-87 



Mi»gnesia(MgO) 6-5.S 



Oxide of IioinFe„03) 1-93 



Chlorine(Cl) 068 



Silica(SiO„) 2-82 



Sulphuric acidlSOj 3-05 



Phosphoric aci(l(P„OJ 10-89 



101-00 100-00 100-5(1 



This is the composition of the ash of the ripe fruit, for it varies 

 considerably at different stages of growth. Thus, unripe apples 

 contain 0-32% of oxide of iron, and 52% of potash; whereas ripe 

 apples contain 1-93% of oxide of iron, and 56% of potash. In the 

 above analyses, there is considerable excess of silica and phos- 

 phoric acid in the quince, and a deficiency of sulphuric acid; but 

 how far these compounds affect the texture of the fruit, it is impos- 

 sible to say. 



The vascular net does not readily separate from the flesh, as in 

 the apple and pear, but is intimately bound up with it. A small 



