18 Anatomy of the Vine.- 



view of them may be seen In Jig. 3., at b c d e, whence they may 

 be traced upwards to s, at which place they pass outwards, and 

 lie in front of the four divisions iklm, as will be fully explained. 

 The ascending vessels carry the sap from the roots to the 

 leaves; and as I intend to describe the ascent of it, in its own 

 natural course, charged with a solution of the prussiate of 

 potash, the following remarks should first be made, that its 

 operation may be well understood : — 



Having observed with what facility water was absorbed by 

 plants of every description, it struck me that it might be 

 charged with a small proportion of some neutral salt, and that 

 it would be readily absorbed by plants when immersed in it. 

 As they naturally bleed when cut, I considered, by the appli- 

 cation of another neutral salt, dissolved in water, to the sepa- 

 rated part, that a visible precipitate would take place upon it. 

 Innumerable experiments have I made with solutions of most 

 of the metallic and alkaline salts, but none succeeded so much 

 to my satisfaction as a solution of the prussiate of potash, of 

 200 grains, dissolved in 16 oz. of water, or as much as a com- 

 mon wine-bottle contains. This fluid is readily absorbed by 

 woody plants, as the flowering, fruit, and forest trees ; and also 

 by annual, biennial, and triennial plants and bulbs : such 

 plants absorb the solution, either by their parts detached, or 

 by their roots when cut. They are to be placed in it, about half 

 an inch deep, for 6, 12, 24, or 36 hours, in proportion to their 

 length and the capacity of their vessels. A vine, for instance, 

 of 6 ft. long, will absorb the solution in 8 hours in a hot day ; 

 while the white lily, cut off a little above the bulb, requires 

 36 hours for the absorption of the fluid into its summit or 

 petals. Plants so treated, when cut through, either trans- 

 versely or longitudinally, will bleed, and the sap or exuding 

 liquid will be impregnated with the prussiate of potash. If a 

 strong solution of the sulphate of iron be applied to the wound r 

 it will form upon it a semi-globule, wherein will be seen, with 

 a moderate magnifying glass, various blue specks, each of 

 which is a precipitate, formed by the union of the prussic acid 

 with the iron. Although I have found these two tests e'ene- 

 rally useful, I have recourse to others, as will be shown, for 

 particular purposes. 



The above statement may be easily proved by cutting off a 

 shoot of a vine, of one year's growth, and placing its lower end 

 in a solution of the above-described prussiate of potash, for a 

 few hours : less time will be required if the shoot be exposed 

 in the sun. On cutting through any of the collets, and apply- 

 ing to the separated parts the sulphate of iron, the ends of the 

 ascending sap-vessels of the alburnum (similar to those in 



