BY D. MCALPIXE. 659 



tributed throughout the pear, strengthen and protect the softer 

 tissues, and being scattered in groups, they olFer no impediment 

 to increase in size. Even the skin, as shown in the account of 

 the apple, acts as an outside skeleton, or exoskeleton, to give 

 firmness to the whole, and keep the component parts together. 

 If the skin is broken or bruised in a ripe pear, it is seen how 

 quickly decay sets in; and even while the fruit is still growing, 

 tlie skin must keep pace with the rapid enlargement. The 

 structure of the skin, with its " window-cells," as in the apple 

 (Fig. 10), is adapted for expansion, but its chief function is to 

 prevent a too rapid loss of water. As showing the efficiency of 

 the skin for this purpose, I had a pear of the Broompark variety 

 and a Jonathan apple, peeled and unpeeled, and kept in a dry 

 atmosphere for 48 hours. The loss in weight was carefully 

 tested by P. R. Scott, Chemist for Agriculture, with the following 

 results : — 



Weight of whole pear before desiccation 261 569 gr. , after 260 0355 gr. 



Weight of peeled pear before desiccation... . 176 677 gr., after 172'5190 gr. 

 Weight of whole apple before desiccation. . 133-4895 gr., after 132737 gr. 

 Weight of peeled apple before desiccation ..112065 gr., after 1088538 gr. 



No.l. Whole pear 0-586 per cent, loss after 48 hours. 



No. 2. Peeled pear 235 ,, ,, „ 



No.3. Whole apple 0563 ,, ,, ,, 



No 4. Peeled apple 2 87 ,, ,, ,, 



Thus the peeled pear had lost over four times the weight of 

 that of the whole pear, and the pared apple had lost over five 

 times that of the unpared. 



The Conducting Tissue. 



If we follow the course of the nutrient fluid, supplied by 

 the root, stem, and leaf, from its entrance through the stalk, 

 to nourish the fruit, it will give us a connected view of the 

 whole system. This food is conveyed through ten primar)' 

 bundles developed in connection with the carpels, although 

 the fleshy portion, which is only accessory to the true fruit, is 

 also nourished through them. The ten primary vascular 

 bundles alternate with each other. Five of them are arranged 

 opposite the five carpels, and each one gives off an internal 



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