FARMERS' REGISTER— EXCRETIONS OF PLANTS. 



159 



of,) the pure Avatcr, wherein a portion of the roots 

 grew, Avas tested, by letting fall a drop or two of 

 the li(iuid oxalate of ammonia into it; when a 

 milkines.^, arising trom the union of the oxalic 

 acid ol" the test with the lime exuded Irom half of 

 the- roots into the pure water, was produced. 

 Such, we may conclude, was tlie nature and result 

 of'one of M. Macaire's experiments, and certainly 

 it IS very conclusive. Oxalate of lime is an al- 

 most insoluble compound; it therelore is manifest- 

 ed in the form of a white powder; the ammonia of 

 Ihc test IS liberated, and distributed through the 

 bullc of the water. 



These chemical experiments arc delightful in 

 themselves, and possess very great interest; but, 

 in the present case, an inquiry of greater moment 

 presents-.itself. Whence came the lime, admitting 

 the fact to be as stated? Nine-tenths of the water 

 of wells, and even ol' many rivers, contain lime in 

 one form or another, and to a certain extent. But 

 the recital states that one portion of the roots was 

 placed in lime-water, and another portion of the 

 roots of the same plant in pure water. IJy this 

 latter term, a chemist understands (Z/siiV/cf/, or per- 

 fectly pure and filtrated jva'/i-water, collected in 

 glass or glazed vessels, as it falls from the clouds. 

 In such water Hme will scarcely be traceable; and, 

 therefore, whatever portion was detected in the 

 pure water, must have passed through the media 

 of the vegetable vessels. "Similar results were 

 made with a weak solution of marine salt" (com- 

 mon table salt,) "and with a like result-" 



The test employed is not stated in the paper, 

 but I conclude it to have been the nitrate of silver, 

 because that chemical preparation is one of the 

 most delicate tests for muriatic acid, in conse- 

 quence of the strong affinity — or rather electro- 

 chemical attraction — which is exerted between 

 that acid and silver whenever tlie latter is held in 

 a state of solution. 

 • Many other experiments are refeiTed to, and all 

 have tended to prove the correctness of the opin- 

 ion, that a rofwfion o/cro/^s fs required, in conse- 

 quence of the excretions from the roots cf plants. 



Having thus adverted to a few of the experi- 

 ments mentioned in the article, I shall now state 

 the facts which led me to the opinion that I formed 

 • above four years since, and in which I have been 

 confirmed by repeated subsequent observations. It 

 was notorious that many crops could not be made 

 to succeed, if repeatedly placed in the same indi- 

 vidual portions of ground. Manures were found 

 ineffectual; and, therefore, the deterioration of the 

 crops coulfl not proceed from a want of sufficient 

 aliment.- The necessity of a rotation was observa- 

 ble chiefly in the farm; still, however, the garden 

 afforded many instances confirmatory of the fact. 

 As I was writing solely upon the produce of the 

 garden, it occurred to me, when treating upon the 

 singular and sudden deterioration of the raspberry, 

 that to the same causes which produced the de- 

 struction of a fruit-bearing shrub, migiit be as- 

 cribed the debility that ever followed the succes- 

 sive repetition of a corn crop upon the farm. I 

 had observed that the soil about the roots of rasp- 

 berries acquired a peculiar color and texture; it 

 differed fl'om that of any other soil of the garden: 

 manure AVas freely applied, and still the plants be- 

 came weaker, shorter in growth, and less fruitful. 

 J did not know the age of my plants, because the 

 bed had been formed before I came into possession 



of the ground; but I really ascertained that plants 

 of the white Antwerp variety, which I purchased 

 and placed along-side of an outermost row of the 

 bed, would not take to the soil; and about the pe- 

 riod that the whole bed became almost worthless, 

 I saw several remarkai)le fine plots of the shrub, 

 and conversed with the owners, from whom I 

 learned a variety of facts, which, though detailed 

 in the plain, unphilosophical manner of cottage 

 gardeners, led me to conclude that the raspberry 

 plant deposited feculent matter in the soil, which, 

 afler a certain period, rendered the sod utterly 

 unfit to support the shrub and enable it to produce 

 fine fruit. Reflection and recollection, at the same 

 time, informed me that a variety of vegetable 

 crops imparted a manifest odor to the soil; so 

 much so, that in digging up a croji, the whole plot 

 was perceived to be imbedded witli a specific aro- 

 ma. I confirmed these facts, and then wrote the 

 passages that I have quoted in the early part ol" 

 this article. Subsequent observations and much 

 experience have confirmed the opmion that I then 

 noted doAvn; so that the reader may rely upon the 

 correctness of the following facts. When peas 

 are sown in pots or boxes, Avilh a vieAV to future 

 transplantation into rows or plots, the vessels be- 

 come replete with matted roots. Upon removing 

 the peas to their place in the garden, the soil they 

 grow in is found to be com])letch' saturated with 

 odorous matter; it emits a powerful peculiar smell, 

 that cannot be mistaken. The kidney-bean (pha- 

 seohis) produces a similar effect, but the odor dif- 

 fers from that of the pea: the same may be ob- 

 served in plants of the leguminous tribe in general; 

 and I have little doubt that this Iribc will be found 

 particularly to require a frequent change of situa- 

 tion. I have already referred to a Avell known 

 effect produced by the pea upon the shallow, loamy 

 soil, of that eastern point of Kent, called the Isle 

 of Tbanet; and the experiment of M. Macaire 

 with the bean ( Vicia Faba) is in accordance with, 

 or at least may be adduced in support of' tlie fi:ictsj 

 named above. 



The Brassica tribe, cabbage, broccoli &c. also 

 impregnate the soil with a marked and peculiar 

 odor. 



From whence do the gases which produce these 

 efl'ects proceed? Many, perhaps, will be inclined 

 to suppose that it is not the soil Avhich gives forth 

 the smell, but the root itself; but how can any 

 plant retain within its substance an odor that'is 

 externally sensible? If a flower, a rose for in- 

 stance, be held at some distance from the nose, 

 the specific aroma of thftt deliglitful flower be- 

 comes manifest; but could this be the case if the 

 rose did not emit the gaseous vapor which dissem- 

 inates the odor? Whatever it "be that yields odor 

 or scent, whether that be acfreeable or offensive, 

 must be material, because it produces a positive 

 eflect upon one of the senses; and, moreover, the^ 

 odor of flowers is very frequently productive of 

 faintness and debility ! If the roots of a plant ra- 

 diate odor, the earth about them, being the me- 

 dium- in Avhich they germinate, must receive the 

 odorific matter; and, in fact, a spade can scarcely 

 be put into a plot of soil that has borne a crop of 

 some vegetables, Avithout liberating, as before 

 stated, a A-olume of vapor sufficient to be dis- 

 cerned, at the distance of a foot or more, above 

 the surface. 



Again, if soil be perfectly fresh, that la to say. 



