83r,.] 



FARMERS' REGISTER. 



651 



they were about three inches long; being placed 

 in a bottle of water, and in the stove, they all 

 emitted roots in a very few days. When these 

 had grown an inch or tvs^o long, I raised each plant 

 without injuring a (ibre, and planicd thcni in three 

 small pols containing the sin)|)lest loam I cuultl 

 find: I mean, by this term, a loam i'rui', from any 

 foreign manuring substance. The plants were 

 potted at the same time, watered with clear water, 

 and set in the stov-e to revive ; in fact, thej- never 

 drooped, but quickly establishing their roots in the 

 loam, began to grow. Intermediately, two^solu- 

 tions were prepared, one of sulphate of iron, 

 brought to the state of peroxide by the addition of 

 a few drops of nitrous acid; the strengih ot' this 

 liquor was so considerable, that the tongue could 

 not conveniently support its asfrincencj^; one- 

 fourth of a Huiil drai-lun, a saturated liquor ot" the 

 peroxide, being added to lour ounces of rain water. 

 The second solution consisted of a drachm of pow- 

 dered Brazil-wood, digested in lour ounces of 

 boiling rain water, strained when cold, and tinged 

 an intense crimson purple by the addition of a lew 

 drops of pure (i. e. caustic) potassa liquor. 



The three [)lants were then treated in the fol- 

 lowing manner — One was marked "Water," the 

 Becond "color," and the third "iron." To the 

 first, pure rain water only was applied, to the 

 second, the extract of Brazil-wood, and to the 

 third, the solution of iron. 



The experiment commenced at the end of July, 

 and was continued till the 17th of August. Tlie 

 plants were always moistened in the way pointed 

 out, with the simjjle exception, that, once or twice, 

 when a powerttjl heat had quite dried the soil of 

 the two balsams artificially treated, a little pure 

 water was given to restore its proper texture. The 

 reader is requested to notice particularly the results 

 now to be stated. The first, marked " water," 

 was healthy, and had grown to the height of a 

 foot; had it been in rich soil, and even in a pot of 

 moderate size, it would have been nmch larger, 

 but the three were retained in the smallest sixties, 

 that is, in vehicles scarcely two hiches wide at the 

 top. 



No. 2, with solution of Brazil-wood, was not 

 quite so vigorous, but it was nearly as tall and 

 liealthy as No. 1. No. 3 was also healthy, but not 

 so tall, and if contracted a sliuht curve in tlie stem. 

 The soil of No. 2, became almost as black as ink ; 

 that of No. 3, had all the appearance of mere rust. 



Now, if the roots of plants while in a natural 

 state, living and growini; in soils, really absorb 

 chemical or vegetable Huids, it ought to follow, 

 that the solution of Biazil-wood, having entered 

 the sap-vessels, would yield a dye of black on the 

 application of a solution of green sulphate of iron. 

 To ascertain the fact, I placed a minute drop of 

 the Brazil liquid on a piece of .white paper, arid 

 applied to it a little drop of the solution of iron, 

 and the formation of ink instantly proved the deli- 

 cacy and correctness of the test. I then cut a 

 slice from the stem of the balsam (No. 2,) and, 

 having a microscope at hand, examined it, and 

 the stem in every way and direction. I called in 

 a witness, one whose eyes were acute in all bo- 

 tanical investigations ; no trace of coloring matter 

 could be discovered, and the iron test produced no 

 effect or discoloration whatsoever. Hence it may 

 be asserted, that the living roots of a balsam, with 

 a white stem; had not taken up the thousandth 



part of a fluid drop of the coloring matter of Bra- 

 zil-wood. No. 3, was then investigated, and the 

 detached portions examined in every way, yet no 

 trace of yellow was perceivable. If water, diluted 

 with even one hundrodtii part of a solution ol" pe- 

 roxide of iron, be tested with prussiiite of potassa 

 (hydrocyanate of potassa,) a blue shade more or 

 less intense will be the inevitable result. This 

 test was rigidly applied, and not a tint of blue, in 

 vessel, cell, or fibre, could be discerned. Hence it 

 was fair to conclude also, that the living balsam, 

 in mould, could not take up the slightest quantity 

 of iron. To make assurance still more sure, two 

 other balsams were tested, one — a rooted plant — 

 was taken from the w-iter without injuring its 

 roots, and placed in a solution of peroxide of iron 

 of the strength described ; it was killed almost in- 

 stantly, and fell withered over the side of the glass 

 vessel. The other was an unrooted cutting. I 

 placed it in a decoction of Brazil-wood, and, so far 

 fi'om striking roots therein (as it would have done 

 fi-eely in water,) it t/ccame sickly, and died in a 

 day or two. 



I draw two important inferences from these ex- 

 periments : theirs/ is, that plants naturally situa- 

 ted, have, by the agency of their vital principle — 

 be that what it may — a power to select and absorb 

 appropriate food ; but that the ground may be so 

 saturated with vicious or unnutritious matters, as 

 to prevent the secretion of a due suppi}' of aliment. 

 Second, that the true sap-vessels act only while the 

 plant remains undisturbed, and in its natural bed. 

 Persons accustomed to vegetable dissection, have 

 flattered themselves, and indeed asserted, that the 

 vessels may be detected by placing cuttings in 

 cofored infusions. Some have also sajd (and this is 

 a tacit admission of a weighty fiict,) that it rooted 

 plants be placed in such infusions, &c. they will 

 absorb, provided the roots be first cut througfi near 

 their points. It appears to me certain, that all in- 

 vestigations conducted witli mutilated subjects, 

 such as cuttings, slips, wounded roots, and the like, 

 tend to mislead the judgment, and to fidsily the in- 

 quiry. I do not venture to assert that there are no 

 exceptions ; but I hesitate not to say that plants in 

 health, living and growing in soil, will not absorb 

 artificial, innutritive substances; they elaborate 

 and secrete ; and the soil is to them an appropriate 

 medium, an adjunct of great consequence, through 

 the texture and composition of which they are 

 enabled to carry on the processes which are essen- 

 tial to their being and support. All mutilations 

 are just so many sophistications, and the inferen- 

 ces deduced from the [jhenomena they atibrd, tend 

 to error and false philosophy. 



That it may not be thought I have introduced a 

 recital which applies to an inquiry into the arrange- 

 ment and offices of the sap-vessels, rather than to 

 one on radical excretion, I must add, that the ex- 

 periments, thouiih directly bearing upon the ques- 

 tion of the conducting vessels of j)lants, leads us 

 to a just appreciation of the value of chemical ex- 

 periments, when performed upon living beings. 

 We perceive plainly that plants, if growing in soil, 

 have a power to reject substances that become ut- 

 terly destr-ijctive when they are applied to the 

 Quaked and unprotected roots; hence we ought to 

 j be very cautious before we receive, with implicit 

 I faith, those hypotheses which may be founded 

 j upon phenomena produced by chemical agents 

 i upon plants artificially situated. I respect the mo- 



