Anatomy of the Vine. 15 



composed of many divisions ; I have found them to vary from 

 40 to 55. Fig. 2. represents a horizontal view of a collet, con- 

 taining a supposed number of 48 of such divisions within 

 abed; but they are there necessarily drawn small, to ex- 

 hibit the whole quantity. But Jig. 3. represents four of them 

 together, on a larger scale, at i Jc I m, that a more perfect 

 idea may be formed of their union. Now, as nature formed 

 every one of these divisions exactly alike, let us avail ourselves 

 of such subdivision, and simplify our investigation, by dis- 

 carding from our minds forty-seven of them and keeping our 

 attention entirely on the remaining one. Jhese divisions act 

 independently of each other in the collet, and are only united 

 by the cellular texture to each other, as will hereafter be more 

 fully explained. 



We will now proceed to simplify again our investigation 

 of this single division, by the assistance of one of the chemical 

 tests ; for, on applying the sulphate of iron, from the third 

 bottle, to the surface, the bark will instantly become disco- 

 loured by various shades, but no alteration will take place 

 on the wood or pith : now, had it not been for this precipi- 

 tate, the various parts of the division would have appeared 

 to the eye so blended together, that it would have been a 

 difficult matter to have pointed out where the bark terminated, 

 or where the woody parts ended. These pleasing effects upon 

 the bark are produced in consequence of their vessels natu- 

 rally containing gallic acid, in a fluid state, similar to the 

 liquid in the second bottle; the sulphate of iron being ap- 

 plied to them produces the black precipitate upon the bark, as 

 before explained, when part of the contents of the second and 

 third bottles were united. 



But the various parts may be still more clearly distinguished 

 from each other, by cutting with a sharp razor a thin slice from 

 a collet, with the assistance of a little regulating screw-machine, 

 which shall be hereafter described. The slice, when taken off, 

 should be placed upon a piece of glass, and moistened with 

 the sulphate of iron by a brush. By looking at the slice held 

 up to the light, through a strong magnifying glass, the various 

 parts of it, particularly the bark, will be distinctly seen. The 

 dark circle is the liber, situated round the wood. As its 

 vessels contain more gallic acid than any other part of the 

 bark, it consequently precipitates a greater proportion of the 

 iron, and thereby produces a more dense colour. The outside 

 of the liber exhibits various lighter shades and figures, which 

 are the parts composing the vascular and cellular texture; 

 the outside of the circle is the cuticle ; within the dark circle 



