VEGETABLE PHYSIOLOGY. 



[LESSON 8. 



sary to grind it down thin enough to transmit light easily, and mount 

 it in fluid as a preparation. 



155. Thin sections of the Peach, Cherry, and Plum stones, show 

 structures not very dissimilar ; these, together with the Hazel-nut, 

 Walnut (English), and Cocoa-nut, so much resemble the ultimate 

 structure of bone, as frequently to be mistaken for it ; there is only 

 one broad character that separates them in bone, the tubes con- 

 nected with the central vesicles (here called canaliculi, or little 

 tubes) freely anastomose (or join) throughout the tissue, whereas in 

 vegetable similar structures, the tubes are confined within the limits 

 of the cell- wall. 



156. The Cherry-stone (Fig. 40) and the Peach-stone, very 

 much resemble each other; in both the like general arrangement 



occurs. 



157. But the culminating point of beauty of these tissues, appears 

 to be the Cocoa-nut, seen in transverse section (Fig. 41). The cells 



FIG. 40. 



FIG. 41. 



Section of Cherry-stone. 



and their internal vesicles are of 

 greatly increased size, as compared 

 with similar structures, and the 

 connecting tubes correspondingly numerous and delicate. 



Transverse section of shell of 

 Cocoa-nut. 



WOODY FIBRE. 



158. Of all the forms of cells, the wood and bass-cells are most 

 important in the domestic economy of mankind. 



159. The " bass-cells " are the longest of all ; their walls are gen- 

 erally very thick, and mostly much bent, but rarely marked with pores 

 or spiral fibres ; only in the silk plant (Asclepias Syriaca), the Olean- 

 der, and allied plants, is a spiral striation of the walls observed. 



160. The materials used for ropes, cordage, linen, certain Indian 

 muslins, mummy cloth, and mats, consist of the woody fibre of plants, 

 from which the more delicate tissues have been removed by long-con- 

 tinued maceration in water. 



