Science of Gardening. QS 1 



quantity obtained from the ashes grew less and less, it would be rasli to infer, 

 from the small excess of lime which was detected, any power belonging to 

 the plant of forming it, when not supplied from without. Should it, however, 

 appear that a vegetable, which, though not perhaps in full vigour, was at least 

 in a growing and healthy condition, remained in contact with strontian, both 

 in the state of sulphate, and likewise in that of nitrate dissolved in water, 

 for months together, without absorbing any portion ; and that, although in 

 want of earthy matter, as its laxity of fibre evidently betrayed; the conclusion 

 would seem to follow, that plants have, to a certain extent, the power, as 

 living agents, of rejecting such substances as, without being poisonous, are 

 unusual to them, and probably unfitted for their economy and structure. 

 Omitting some previous experiments, of which I have preserved no correct 

 notes, 1 will, in the first instance, refer to one made in 1827, in which grasses 

 and trefoils of various kinds, v/hich had been watered from time to time with 

 a solution of nitrate of strontian, were found, on examination, to possess no 

 trace of this earth. In the above instance, however, as the plants had grown 

 in common garden mould, all that could be inferred was, that, when lime and 

 strontian are both presented in a state of solution to their roots, they select 

 the former, and reject the latter. In 1829, the seeds of various plants, such 

 as the garden radish (iJaphanus sativus), the cabbage (^rassica oleracea), 

 the garden bean ( Ticia jPaba), hemp (Cannabis sativa), &c., were sown in 

 soils containing various proportions of sulphate of strontian, with or without 

 manure, and, amongst the rest, one in which no other ingredient except this 

 earth was present in any quantity. The plants grew up ; and when they had 

 arrived at maturity were collected, burnt, and their ashes examined. No 

 strontian, however, could be detected in any one of them; not even in that 

 where the matrix consisted almost wholly of the earth in question. In 1831, 

 the experiments were conducted with rather more attention to accuracy. 

 1 124 grains of scarlet kidneybeans (Phaseolus multifiorus) were sown in a box 

 containing about 2901b. of powdered sulphate of strontian, which has been 

 ascertained to be free from alkaline matter, but to contain 2 per cent of car- 

 bonate of lime, and about i per cent of alumina. The box was placed in an 

 open situation, exposed to sun and rain ; and when the plants reared from 

 these seeds had come to maturity, they were cut down and burnt. An ac- 

 count was then taken of the weight of the ashes remaining after the com- 

 bustion had been completed, and of the fixed principles obtained from them ; 

 first, by Hxiviation in water ; secondly, by digestion in nitric acid ; and, thirdl}^, 

 by treating the remainder with an alkaline carbonate, and then again with the 

 same acid as before. A similar process was gone through with the same 

 quantity of the kidneybeans as that of which the plants examined had been 

 the produce," {Edinburgh Neiu Philosophical Journal, p. 164.) 



After relating a number of experiments, and giving tabular views of their 

 results. Dr. Daubeny continues : — 



" I fear the conclusions that may be legitimately deduced from the above 

 experiments will hardly be deemed of sufficient novelty and importance to 

 repay the labour and time they have cost me ; since, in so far as the main 

 point is concerned, they serve only to confirm, in an indirect manner, the 

 conclusion which both analogy and experiment concur in establishing ; 

 namely, that if plants do, in some cases, obtain fixed principles, which 

 cannot be traced to any external source, yet the quantity of such sub- 

 stances which enters into their system is always less in proportion to the 

 pains taken to cut oft" a supply. Hence the inference would seem to be, that 

 the indications of a contrary description, that sometimes present themselves, 

 are fallacious, resulting from the many imperceptible channels by which 

 earthy and alkaline matters may obtain admission to the juices of a plant. 

 Had I not, very early in the course of these experiments, been led to despair 

 of excluding the minute but continual supplies which are probably brought 

 by the very air and water which come into contact with the absorbing sur- 

 faces of every vegetable, especially in the centre of a large town, I should not 



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