262 Anatomy of the Vine. 



smooth grain from any oak board ; or it may be produced, by 

 planing away the concentric layer, keeping all the time an 

 attentive eye upon the outside edges of the cellular texture, as 

 a guide to regulate how much is to be removed : when a 

 broadish surface of cellular texture is produced, any device of 

 birds or beasts may be drawn upon it ; afterwards cut away 

 the extra-quantity, which exceeds the figures of your design, 

 and form a smooth surface of concentric layer a little lower 

 than the former. 



The vessels of many seeds contain the close cellular, as 

 wheat, beans, peas, &c. \ and these may be dried so much as 

 to become as hard as box-wood. Roots, in general, contain 

 the extended cellular vessels, as potatoes, carrots, turnips, &c. ; 

 but these are all perishable. 



Two pleasing experiments may be performed upon the bean 

 and potato, by placing them in a solution of the prussiate of 

 potash. Cut them through the middle when the root of the 

 former and the eyes of the latter are a very little elongated, 

 and apply to their surface the sulphate of iron ; when they 

 will both exhibit, with the assistance of the microscope, the 

 contours or framework of their cellular vessels, by the blue 

 precipitate forming a most beautiful ramification between the 

 cells : although the cells themselves will not exhibit any 

 precipitate, because they have not admitted internally any of 

 the prussiate of potash ; for they are full of the former sum- 

 mer's secreted juice, laid up within them, to nourish their 

 embryo or extending shoots during their infantine state. 



The potato affords a further gratifying experiment. Cut 

 one unprepared, through the middle ; dry its surface a little 

 with blotting paper, then apply to it the spirituous tincture 

 of iodine, when a black precipitate will be immediately pro- 

 duced ; this is the iodate of starch, because the iodine has 

 united with the farinaceous liquid from the cells of the vessels- 

 Slightly raise with the point of a fine needle one of the entire 

 cells, afterwards puncture it with the point, which will dis- 

 charge a clear liquor, but it will be immediately precipitated 

 by the iodine into which it flows. If you leave some small 

 pieces of the potato cut asunder for a few days, the fluid in 

 their cells will be found to be opaque, which shows that they 

 ceased to retain their vital principle. These extended cellular 

 vessels are again pleasingly exhibited by examining those of 

 a boiled potato, when every one will readily separate and 

 appear like a grain of white sand. 



It is frequently desirable to examine the cellular vessels of 

 the potato, turnip,' apple, &c, but which it is difficult to do, 

 from their transparency and extreme minuteness. The fol- 

 lowing method I should recommend ; it will take but a minute 



