Anatomy of the Vine. 2 1 



reducing their number to three or four, or even one division, 

 the same result will ensue. 



I beg to observe that no part of the substance of the actual 

 concentric layer (see Jig. 4. at g g, and^g. 3. at n n.) is con- 

 tinued into the stalks or leaves ; had the ligneous fibres of the 

 concentric layer extended into them, it would have caused the 

 stalks and leaves to have permanently remained upon the trees, 

 after they had performed their summer's office, and appeared 

 an unsightly incumbrance of dry materials; but the whole 

 being of a perishable nature, they drop off as soon as their 

 vital principle ceases to act. What a remarkable instance is 

 this of Nature preserving the beauty of her works, as well as 

 of a further provision that their decomposition or decay should 

 become the future food of plants ! We have frequent instances 

 of this fact, by the luxuriant growth of trees in many woods, 

 where the herbage that surrounds such woods, growing on the 

 same kind of soil, is scarcely sufficient to feed a few sheep. 



The Liber I shall now partially describe ; it is the inward 

 substance of the bark, and joins the alburnum. In a large, 

 healthy, summer shoot of the vine, it will be found to be 

 about one tenth of an inch thick ; but, in order to examine 

 it minutely, a very thin slice should be cut from a collet by 

 the little regulating machine, as mentioned before, and moist- 

 ened with the solution of the sulphate of iron ; then, with the 

 assistance of two powerful magnifying glasses connected toge- 

 ther, the liber will be distinctly seen ; and, upon an attentive 

 examination, it will be found to consist of two bars of ligneous 

 vessels {Jig. 4. e e) lying between three bars of other vessels 

 (d d d), which latter appear in their early state to be some- 

 what of a fleshy elastic substance, but in their more matured 

 state, they become woody, and are nearly hexagonal-shaped 

 vessels. They are only acted upon by the sulphate of iron, 

 from their containing gallic acid, so that the two substances in 

 the liber may be easily distinguished from each other by the 

 black precipitate upon the fleshy vessels ddd, when none will 

 be seen on the ligneous vessels e e. 



Fig. 3. represents part of the perpendicular vessels of a 

 division, cut down the middle ; ffjf are those of the liber, 

 consisting of the three dark and two white lines, similar to 

 those on a larger scale in Jig. 4. d dd d, and e e. The liber 

 is invariably placed on the outside of the alburnum, whether 

 in the root, stem, or branch of the vine ; but, in the claw, stalk, 

 and leaf, it covers only the ascending sap and spiral vessels. 

 It is the principal agent in forming the alburnum, which will 

 be shown when I explain its gradual growth or increase. 



c 3 



